diff --git a/scripts/pack-act-assets.ts b/scripts/pack-act-assets.ts
index ebb47fc..638a55f 100644
--- a/scripts/pack-act-assets.ts
+++ b/scripts/pack-act-assets.ts
@@ -30,7 +30,7 @@ import { join } from 'node:path'
 import { MpqArchive } from '../src/mpq/archive.ts'
 import { fileSource } from '../src/mpq/file-source.ts'
 import { MountedArchives } from '../src/mpq/mount.ts'
-import { cell, loadActTables, parseTable, resolveLevel, resolveLevelLibraries, tileMemberPath } from '../src/game/acts.ts'
+import { cell, loadActTables, parseTable, resolveLevel, resolveLevelLibraries, tileMemberPath, ACT_TOWNS } from '../src/game/acts.ts'
 import type { ActTables, LevelInfo, D2Table } from '../src/game/acts.ts'
 import { decodeDs1 } from '../src/formats/ds1.ts'
 import type { Ds1 } from '../src/formats/ds1.ts'
@@ -366,9 +366,6 @@ const monstersTable = {
  */
 const ACT_LAYOUT_SEED = 0x5eed_2000
 
-/** Where each act's town is, for working out which way is "up" in a dungeon. */
-const ACT_TOWNS: readonly number[] = [1, 40, 75, 103, 109]
-
 const worldGraph: WorldGraph = assignGateSides(
   buildWorldGraph(parseLevelRows(tables.levels)),
   ACT_LAYOUT_SEED,
@@ -544,6 +541,7 @@ function buildSceneLinks(
   const outEntrances: SceneEntrance[] = []
   const outWarps: SceneWarp[] = []
   const unplaced: { toLevelId: number; reason: string }[] = []
+  const notes: string[] = []
   const placedSeams = new Set<number>()
   const placedWarps = new Set<number>()
 
@@ -754,6 +752,9 @@ function buildSceneLinks(
       unplaced.push({ toLevelId: edge.to, reason: 'no walkable ground for a fallback warp' })
       return
     }
+    const fromName = worldGraph.levels.get(levelId)?.name ?? `level ${String(levelId)}`
+    const toName = worldGraph.levels.get(edge.to)?.name ?? `level ${String(edge.to)}`
+    notes.push(`fallback warp placed for edge ${fromName} -> ${toName}`)
     outWarps.push(makeWarp(
       edge,
       directionTo(edge.to),
@@ -800,7 +801,7 @@ function buildSceneLinks(
     }
   }
 
-  return { entrances: outEntrances, warps: outWarps, waypoints, unplacedEdges: unplaced }
+  return { entrances: outEntrances, warps: outWarps, waypoints, unplacedEdges: unplaced, notes }
 }
 
 const allNames = await archives.listFiles()
@@ -1160,6 +1161,7 @@ async function bakeDs1Variant(
     readonly mazeWarps: readonly MazeWarp[]
     readonly mazeWaypoints?: readonly MazeWaypoint[]
     readonly landmarks?: readonly { readonly id: string; readonly tileX: number; readonly tileY: number }[]
+    readonly notes?: readonly string[] | undefined
   } = { entrances: [], mazeWarps: [] },
 ): Promise<void> {
   const scene: IsoMapScene = buildIsoMapScene(level, libraries, seed)
@@ -1448,6 +1450,10 @@ async function bakeDs1Variant(
       // Edges the world graph has that this copy of the level has nowhere to
       // put. Reported rather than dropped: each one is a hole in the world.
       unplacedEdges: sceneLinks.unplacedEdges,
+      notes: [
+        ...(generatorLinks.notes ?? []),
+        ...(sceneLinks.notes ?? []),
+      ],
     },
   }
   const sceneBytes = new TextEncoder().encode(JSON.stringify(sceneJson))
@@ -1652,6 +1658,7 @@ for (const entry of LEVELS) {
             ...(Array.isArray(result.stats.landmarkEntities)
               ? { landmarks: result.stats.landmarkEntities as readonly { readonly id: string; readonly tileX: number; readonly tileY: number }[] }
               : {}),
+            ...(Array.isArray(result.stats.notes) ? { notes: result.stats.notes } : {}),
           },
         )
       } catch (err) {
diff --git a/scripts/verify-packs.ts b/scripts/verify-packs.ts
index a08ffb8..3d9c4bb 100644
--- a/scripts/verify-packs.ts
+++ b/scripts/verify-packs.ts
@@ -295,7 +295,10 @@ interface PackedLinks {
     readonly source?: 'tile' | 'room' | 'fallback'
   }[]
   readonly waypoints?: readonly { readonly waypointId: number }[]
-  readonly stats?: { readonly unplacedEdges?: readonly { readonly toLevelId: number; readonly reason: string }[] }
+  readonly stats?: {
+    readonly unplacedEdges?: readonly { readonly toLevelId: number; readonly reason: string }[]
+    readonly notes?: readonly string[]
+  }
 }
 
 const graph = JSON.parse(await readFile(join(packDir, 'world-graph.json'), 'utf8')) as PackedWorldGraph
@@ -385,13 +388,24 @@ for (const key of orphanEdges.slice(0, 20)) {
 }
 check(orphanEdges.length === 0, `world: no graph edge left without an opening (${String(orphanEdges.length)} orphans)`)
 
-// Not an assertion: an approximate staircase is traversable, just not authentic.
-// The number is printed every run so it cannot creep up unnoticed, and it only
-// falls when a level type's DRLG staircase pass gets transcribed.
+// Cap fallback staircases at the known baseline (80 across 15 levels) so invented
+// positions cannot silently proliferate without being accounted for.
+const MAX_EXPECTED_FALLBACK_WARPS = 80
+check(
+  warpSources.fallback <= MAX_EXPECTED_FALLBACK_WARPS,
+  `world: fallback warps (${String(warpSources.fallback)}) within expected threshold (<= ${String(MAX_EXPECTED_FALLBACK_WARPS)})`,
+)
+
 console.log(
   `\n楼梯来源：美术瓦片 ${String(warpSources.tile)}，迷宫楼梯间 ${String(warpSources.room)}，`
   + `兜底 ${String(warpSources.fallback)}（涉及 ${String(approximateLevels.size)} 个关卡）`,
 )
+if (approximateLevels.size > 0) {
+  const breakdown = [...approximateLevels]
+    .map(id => `${String(id)} (${graphLevelName.get(id) ?? 'unknown'})`)
+    .join(', ')
+  console.log(`   兜底关卡列表: ${breakdown}`)
+}
 
 console.log(`\n${String(checks - failures)}/${String(checks)} 项断言通过（逐像素比对了 ${(comparedPixels / 1048576).toFixed(1)} MB 的索引数据）`)
 if (failures > 0) process.exit(1)
diff --git a/scripts/verify-world-graph.ts b/scripts/verify-world-graph.ts
index 9d83983..f6bccb6 100644
--- a/scripts/verify-world-graph.ts
+++ b/scripts/verify-world-graph.ts
@@ -33,7 +33,7 @@ import { readFileSync } from 'node:fs'
 import { MountedArchives } from '../src/mpq/mount.ts'
 import { MpqArchive } from '../src/mpq/archive.ts'
 import { fileSource } from '../src/mpq/file-source.ts'
-import { loadActTables } from '../src/game/acts.ts'
+import { loadActTables, ACT_TOWNS } from '../src/game/acts.ts'
 import {
   parseLevelRows,
   buildWorldGraph,
@@ -56,8 +56,6 @@ const dir = process.argv[2] ?? 'samples/d2'
 const MOUNTS = ['d2data.mpq', 'd2exp.mpq', 'Patch_D2.mpq']
 /** The baked asset packs. */
 const PACK_INDEX = 'samples/d2-packs/index.json'
-/** The town of each act, keyed by the 0-based `Act` column. */
-const ACT_TOWNS: readonly number[] = [1, 40, 75, 103, 109]
 /** Waypoint ids run 0..38 with no gaps. */
 const WAYPOINT_COUNT = 39
 /** How many seeds to exercise the side solver with. */
diff --git a/src/game/acts.ts b/src/game/acts.ts
index 6d10208..6d3dc41 100644
--- a/src/game/acts.ts
+++ b/src/game/acts.ts
@@ -183,6 +183,28 @@ export interface LevelInfo {
  */
 export type ActTown = LevelInfo
 
+/**
+ * Town level IDs for Acts 1..5 in order:
+ * Act 1: Rogue Encampment (1)
+ * Act 2: Lut Gholein (40)
+ * Act 3: Kurast Docks (75)
+ * Act 4: The Pandemonium Fortress (103)
+ * Act 5: Harrogath (109)
+ */
+export const ACT_TOWNS: readonly number[] = [1, 40, 75, 103, 109]
+
+/**
+ * Returns the town level ID for an act (1..5).
+ * Defaults to Act 5 Harrogath (109) for acts >= 5, or Act 1 Rogue Encampment (1) for acts <= 1.
+ */
+export function townLevelForAct(act: number): number {
+  if (act >= 1 && act <= 5) {
+    return ACT_TOWNS[act - 1]!
+  }
+  if (act <= 1) return ACT_TOWNS[0]!
+  return ACT_TOWNS[4]!
+}
+
 /** Turn a table-relative tile path into a member name. */
 export function tileMemberPath(relative: string): string {
   return `${TILES}${relative.replaceAll('/', '\\')}`
diff --git a/src/game/level-links.ts b/src/game/level-links.ts
index 9ddd762..7d32da6 100644
--- a/src/game/level-links.ts
+++ b/src/game/level-links.ts
@@ -180,6 +180,8 @@ export interface SceneLinks {
    * hole in the world, and the verifier reports on this list.
    */
   readonly unplacedEdges: readonly { readonly toLevelId: number; readonly reason: string }[]
+  /** Diagnostic notes and warnings from link resolution (e.g. fallback warps placed). */
+  readonly notes?: readonly string[]
 }
 
 /**
@@ -394,7 +396,8 @@ export function seamArrivalSpot(
   const step = inwardStep(side)
   const targetX = x + step.x * (SEAM_TRIGGER_SUBTILES + 3)
   const targetY = y + step.y * (SEAM_TRIGGER_SUBTILES + 3)
-  for (let radius = 0; radius <= 32; radius += 1) {
+  const maxRadius = Math.max(grid.gridWidth, grid.gridHeight, 64)
+  for (let radius = 0; radius <= maxRadius; radius += 1) {
     for (let dy = -radius; dy <= radius; dy += 1) {
       for (let dx = -radius; dx <= radius; dx += 1) {
         if (Math.max(Math.abs(dx), Math.abs(dy)) !== radius) continue
@@ -406,7 +409,14 @@ export function seamArrivalSpot(
       }
     }
   }
-  return nearestWalkable(grid, targetX, targetY, 32, region) ?? { x, y }
+  // Never place the player directly back on or inside the trigger box around (x, y),
+  // which would trigger an immediate bounce back in an infinite ping-pong loop.
+  const clampedX = Math.max(0, Math.min(grid.gridWidth - 1, targetX))
+  const clampedY = Math.max(0, Math.min(grid.gridHeight - 1, targetY))
+  if (Math.abs(clampedX - x) <= SEAM_TRIGGER_SUBTILES && Math.abs(clampedY - y) <= SEAM_TRIGGER_SUBTILES) {
+    return { x: targetX, y: targetY }
+  }
+  return { x: clampedX, y: clampedY }
 }
 
 /** Where an edge of a level opens, and how convincing the opening is. */
diff --git a/src/game/maze-special-passes.ts b/src/game/maze-special-passes.ts
index d10f12c..471125e 100644
--- a/src/game/maze-special-passes.ts
+++ b/src/game/maze-special-passes.ts
@@ -15,6 +15,7 @@
  * - `DRLGMAZE_ScanReplaceSpecialAct2SewersPresets`: Lut Gholein Sewers (Radament's Lair & Atma's quest).
  */
 
+import { Rng } from './rng.ts'
 import {
   DIRECTION_WEST,
   DIRECTION_NORTH,
@@ -56,6 +57,11 @@ export interface SpecialPassContext {
   readonly pieces: readonly MazePiece[]
   readonly index: PieceIndex
   readonly stats: MazeStats
+  readonly rng?: Rng
+}
+
+function getPassRng(ctx: SpecialPassContext): Rng {
+  return ctx.rng ?? ctx.level?.rng ?? new Rng(ctx.request.seed)
 }
 
 const DIRS = ['N', 'E', 'S', 'W'] as const
@@ -189,6 +195,7 @@ export function placeNamedPiece(
  * Horadric Cube chest, Leatherarm, and staircases.
  */
 export function placeAct2TombStuff(ctx: SpecialPassContext): void {
+  const rng = getPassRng(ctx)
   const levelId = ctx.request.levelId
   const staffTomb = ctx.request.staffTombLevelId ?? 66
   const bossTomb = ctx.request.bossTombLevelId
@@ -202,9 +209,9 @@ export function placeAct2TombStuff(ctx: SpecialPassContext): void {
     else if (name.includes('NEW')) nDirection = 1
     else if (name.includes('NSE')) nDirection = 2
     else if (name.includes('SEW')) nDirection = 3
-    else nDirection = ctx.request.seed % 4
+    else nDirection = rng.int(0, 3)
   } else {
-    nDirection = ctx.request.seed % 4
+    nDirection = rng.int(0, 3)
   }
 
   const GROW_DIRS = [DIRECTION_SOUTH, DIRECTION_WEST, DIRECTION_NORTH, DIRECTION_EAST]
@@ -279,6 +286,7 @@ export function placeAct2TombStuff(ctx: SpecialPassContext): void {
  * Level 3 places Coldworm the Burrower (Tight Spot S) and the Staff of Kings chest (Treasure W).
  */
 export function placeAct2LairStuff(ctx: SpecialPassContext): void {
+  const rng = getPassRng(ctx)
   const levelId = ctx.request.levelId
 
   if (levelId === 64) {
@@ -309,7 +317,7 @@ export function placeAct2LairStuff(ctx: SpecialPassContext): void {
       preferFurthest: false,
     })
   } else {
-    const nRand = ctx.request.seed % 4
+    const nRand = rng.int(0, 3)
     placeNamedPiece(ctx, {
       kind: 'next',
       namePrefix: 'Act 2 - Lair Next',
@@ -339,8 +347,9 @@ export function placeAct2LairStuff(ctx: SpecialPassContext): void {
  * Temples (levels 94..99) place Lam Esen's Tome altar.
  */
 export function placeAct3DungeonStuff(ctx: SpecialPassContext): void {
+  const rng = getPassRng(ctx)
   const levelId = ctx.request.levelId
-  const nDirection = ctx.request.seed % 4
+  const nDirection = rng.int(0, 3)
 
   if (levelId === 91) {
     // Flayer Dungeon Level 3: Khalim's Brain chest
@@ -404,8 +413,9 @@ export function placeAct3DungeonStuff(ctx: SpecialPassContext): void {
  * Level 1 places the drain descent lever and staircase down to Level 2.
  */
 export function placeAct3SewerStuff(ctx: SpecialPassContext): void {
+  const rng = getPassRng(ctx)
   const levelId = ctx.request.levelId
-  const nDirection = ctx.request.seed % 4
+  const nDirection = rng.int(0, 3)
 
   if (levelId === 92) {
     // Sewer Level 1: Drain lever / stairs down to Sewer 2
@@ -454,8 +464,9 @@ export function placeAct3SewerStuff(ctx: SpecialPassContext): void {
  * Level 2 places Waypoint, Next and Prev.
  */
 export function placeAct3MephistoStuff(ctx: SpecialPassContext): void {
+  const rng = getPassRng(ctx)
   const levelId = ctx.request.levelId
-  const nRand = ctx.request.seed % 4
+  const nRand = rng.int(0, 3)
 
   if (levelId === 102) {
     // Durance of Hate Level 3: Mephisto Complex
@@ -526,6 +537,7 @@ export function placeAct3MephistoStuff(ctx: SpecialPassContext): void {
  * Halls of Pain (level 123) places Waypoint and descent stairs.
  */
 export function placeAct5TempleStuff(ctx: SpecialPassContext): void {
+  const rng = getPassRng(ctx)
   const levelId = ctx.request.levelId
 
   if (levelId === 124) {
@@ -547,7 +559,7 @@ export function placeAct5TempleStuff(ctx: SpecialPassContext): void {
   } else {
     // Levels 122 and 123
     const templeDownDirs = ['NE', 'NW', 'SW']
-    const nDirection = (ctx.request.seed >>> 0) % 3
+    const nDirection = rng.int(0, templeDownDirs.length - 1)
     const downSide = templeDownDirs[nDirection]!
 
     placeNamedPiece(ctx, {
@@ -560,7 +572,7 @@ export function placeAct5TempleStuff(ctx: SpecialPassContext): void {
 
     if (levelId === 123) {
       const templeWaypointDirs = ['NE', 'NW', 'SW', 'SE']
-      const wpSide = templeWaypointDirs[(nDirection + 1) % 4]!
+      const wpSide = templeWaypointDirs[rng.int(0, templeWaypointDirs.length - 1)]!
       placeNamedPiece(ctx, {
         kind: 'waypoint',
         name: `Act 5 - Temple ${wpSide} Waypoint`,
@@ -591,8 +603,9 @@ export function placeAct5TempleStuff(ctx: SpecialPassContext): void {
  * Worldstone Keep 2 places Waypoint and Next stairs.
  */
 export function placeAct5BaalStuff(ctx: SpecialPassContext): void {
+  const rng = getPassRng(ctx)
   const levelId = ctx.request.levelId
-  const nDirection = ctx.request.seed % 4
+  const nDirection = rng.int(0, 3)
 
   if (levelId === 131) {
     // Throne of Destruction
@@ -657,11 +670,12 @@ export function placeAct5BaalStuff(ctx: SpecialPassContext): void {
  * Glacial Trail (115) places Theme and Waypoint.
  */
 export function placeAct5IceStuff(ctx: SpecialPassContext): void {
+  const rng = getPassRng(ctx)
   const levelId = ctx.request.levelId
 
   if (levelId === 114) {
     // Frozen River (Anya platform)
-    const variant = (ctx.request.seed % 2) === 0 ? 'A' : 'B'
+    const variant = rng.int(0, 1) === 0 ? 'A' : 'B'
     if (ctx.level.rooms.length === 1 && ctx.level.first !== null) {
       const riverPiece = ctx.pieces.find(p => p.name === `Act 5 - Ice River ${variant}`)
         ?? ctx.pieces.find(p => p.name.startsWith('Act 5 - Ice River'))
@@ -701,7 +715,7 @@ export function placeAct5IceStuff(ctx: SpecialPassContext): void {
     placeNamedPiece(ctx, { kind: 'quest', name: 'Act 5 - Ice Pool B', preferFurthest: true })
   } else {
     // Levels 113, 115, 118
-    let nDirection = ctx.request.seed % 4
+    let nDirection = rng.int(0, 3)
     placeNamedPiece(ctx, {
       kind: 'prev',
       namePrefix: 'Act 5 - Ice Prev',
@@ -760,6 +774,7 @@ export function placeAct5IceStuff(ctx: SpecialPassContext): void {
  * Places Court Connect, the Smith / Charsi's Malus forge, and stairs to Jail.
  */
 export function placeAct1Barracks(ctx: SpecialPassContext): void {
+  const rng = getPassRng(ctx)
   // Connect towards Outer Cloister
   placeNamedPiece(ctx, {
     kind: 'prev',
@@ -768,8 +783,8 @@ export function placeAct1Barracks(ctx: SpecialPassContext): void {
     preferFurthest: false,
   })
 
-  const nDirection = ctx.request.seed % 4
-  const roll = (ctx.request.seed >>> 2) % 2
+  const nDirection = rng.int(0, 3)
+  const roll = rng.int(0, 1)
 
   if (roll === 1) {
     placeNamedPiece(ctx, {
@@ -815,6 +830,7 @@ export function placeAct1Barracks(ctx: SpecialPassContext): void {
  * Hephasto the Armorer / Hellforge, and fills blanks with Lava X.
  */
 export function placeAct4Lava(ctx: SpecialPassContext): void {
+  const rng = getPassRng(ctx)
   // 1. Warp N (entrance from City of Damned)
   placeNamedPiece(ctx, {
     kind: 'prev',
@@ -840,7 +856,7 @@ export function placeAct4Lava(ctx: SpecialPassContext): void {
   })
 
   // 3. Hellforge (Hephasto the Armorer)
-  const forgeSide = (ctx.request.seed % 2) === 0 ? 'W' : 'E'
+  const forgeSide = rng.int(0, 1) === 0 ? 'W' : 'E'
   placeNamedPiece(ctx, {
     kind: 'quest',
     name: `Act 4 - Lava Forge ${forgeSide}`,
@@ -865,8 +881,9 @@ export function placeAct4Lava(ctx: SpecialPassContext): void {
  * Ancient Tunnels (level 50) places Chest and Prev.
  */
 export function scanReplaceSpecialAct2SewersPresets(ctx: SpecialPassContext): void {
+  const rng = getPassRng(ctx)
   const levelId = ctx.request.levelId
-  let nRand = ctx.request.seed % 4
+  let nRand = rng.int(0, 3)
 
   if (levelId === 49) {
     // Sewers Level 3: Radament's Lair
diff --git a/src/game/maze.ts b/src/game/maze.ts
index c6b70fd..bfc2cf6 100644
--- a/src/game/maze.ts
+++ b/src/game/maze.ts
@@ -2271,6 +2271,7 @@ export function generateMaze(request: MazeRequest): MazeResult {
         pieces: request.pieces,
         index,
         stats,
+        rng,
       })
     }
   }
diff --git a/src/game/portal.ts b/src/game/portal.ts
index da4ded1..f59db5c 100644
--- a/src/game/portal.ts
+++ b/src/game/portal.ts
@@ -213,27 +213,4 @@ export class TownPortalSlot {
   }
 }
 
-/**
- * The town for an act.
- *
- * Hard-coded because `Levels.txt` does not mark towns: the Rogue Encampment's
- * row looks like any other preset. The ids are stable across every version of
- * the game.
- *
- * @param act - the act, 1..5.
- * @returns the town's level id.
- */
-export function townLevelForAct(act: number): number {
-  switch (act) {
-    case 1:
-      return 1
-    case 2:
-      return 40
-    case 3:
-      return 75
-    case 4:
-      return 103
-    default:
-      return 109
-  }
-}
+export { ACT_TOWNS, townLevelForAct } from './acts.ts'
diff --git a/src/game/wilderness.ts b/src/game/wilderness.ts
index 05e7df1..55e3ba1 100644
--- a/src/game/wilderness.ts
+++ b/src/game/wilderness.ts
@@ -325,6 +325,8 @@ export interface WildernessResult {
   /** What the generator did, for reporting and tests. */
   readonly stats: Record<string, unknown> & {
     readonly landmarkEntities?: LandmarkEntity[]
+    readonly notes?: string[]
+    readonly unresolved?: string[]
   }
 }
 
@@ -1405,6 +1407,7 @@ export function getPerimeterOpenings(
   levelId: number,
   gridWidth: number,
   gridHeight: number,
+  gates?: readonly PlannedGate[],
 ): Set<string> {
   const openings = new Set<string>()
   const key = (x: number, y: number) => `${String(x)},${String(y)}`
@@ -1414,25 +1417,32 @@ export function getPerimeterOpenings(
     return openings
   }
 
-  // Outdoor wilderness levels across Acts 1, 2, 3, 4, 5:
-  // Act 1 (2..7), Act 2 desert (41..46), Act 3 Kurast (79..82),
-  // Act 4 Mesa (104..106), Act 5 outdoor (111..112, 117):
-  // Default entrance on South edge, exit on East edge
-  if (
-    (levelId >= 2 && levelId <= 7) ||
-    (levelId >= 41 && levelId <= 46) ||
-    (levelId >= 79 && levelId <= 82) ||
-    (levelId >= 104 && levelId <= 106) ||
-    (levelId >= 111 && levelId <= 112) ||
-    levelId === 117
-  ) {
-    const inX = Math.floor(gridWidth / 2)
-    openings.add(key(inX, gridHeight - 1))
-    const outY = Math.floor(gridHeight / 2)
-    openings.add(key(gridWidth - 1, outY))
+  if (gates !== undefined && gates.length > 0) {
+    for (const gate of gates) {
+      switch (gate.side) {
+        case 'north':
+          openings.add(key(Math.floor(gridWidth / 2), 0))
+          break
+        case 'south':
+          openings.add(key(Math.floor(gridWidth / 2), gridHeight - 1))
+          break
+        case 'west':
+          openings.add(key(0, Math.floor(gridHeight / 2)))
+          break
+        case 'east':
+          openings.add(key(gridWidth - 1, Math.floor(gridHeight / 2)))
+          break
+      }
+    }
     return openings
   }
 
+  // Outdoor wilderness levels across Acts 1..5:
+  // Default entrance on South edge, exit on East edge so borders are never sealed shut
+  const inX = Math.floor(gridWidth / 2)
+  openings.add(key(inX, gridHeight - 1))
+  const outY = Math.floor(gridHeight / 2)
+  openings.add(key(gridWidth - 1, outY))
   return openings
 }
 
@@ -1458,6 +1468,7 @@ export function getPerimeterOpenings(
  * @param levelId - optional level id for perimeter opening rules.
  * @param openGates - optional map from `${x},${y}` block key to forced variant index.
  * @param claimedBorderBlocks - optional set of `${x},${y}` keys to skip (e.g. Town Transitions).
+ * @param gates - optional planned gates from the world graph.
  * @returns the number of pieces stamped.
  */
 function layBorder(
@@ -1470,6 +1481,7 @@ function layBorder(
   levelId?: number,
   openGates?: ReadonlyMap<string, number>,
   claimedBorderBlocks?: ReadonlySet<string>,
+  gates?: readonly PlannedGate[],
 ): number {
   if (pieces.length === 0) {
     stats.unresolved.push('no border piece for this level type')
@@ -1512,7 +1524,12 @@ function layBorder(
     { x: 0, y: gridHeight - 1 }, // SW
   ]
 
-  const openings = levelId !== undefined ? getPerimeterOpenings(levelId, gridWidth, gridHeight) : new Set<string>()
+  const openings = levelId !== undefined ? getPerimeterOpenings(levelId, gridWidth, gridHeight, gates) : new Set<string>()
+  if (openGates !== undefined) {
+    for (const gateKey of openGates.keys()) {
+      openings.add(gateKey)
+    }
+  }
 
   let cursor = rng.int(0, ordered.length - 1)
   let stamped = 0
@@ -1673,6 +1690,7 @@ function planAct1OutdoorLevel(
   gridWidth: number,
   gridHeight: number,
   rng: Rng,
+  stats?: WildernessStats,
 ): Act1OutdoorPlan {
   const openGates = new Map<string, number>()
   const claimedBorderBlocks = new Set<string>()
@@ -1802,13 +1820,21 @@ function planAct1OutdoorLevel(
     toLevelId?: number,
   ): boolean => {
     const piece = findPiece(prefix)
-    if (piece === undefined || piece.levels.length === 0) return false
+    if (piece === undefined || piece.levels.length === 0) {
+      stats?.unresolved.push(`preset piece not found: ${prefix}`)
+      stats?.notes.push(`failed to place preset: ${label} (missing piece ${prefix})`)
+      return false
+    }
     const variant = rng.int(0, piece.levels.length - 1)
     const ds1 = piece.levels[variant]!
     const blocksX = Math.max(1, Math.floor(ds1.width / TILES_PER_BLOCK))
     const blocksY = Math.max(1, Math.floor(ds1.height / TILES_PER_BLOCK))
     const pos = pickFreeInteriorBox(blocksX, blocksY, 2)
-    if (pos === null) return false
+    if (pos === null) {
+      stats?.unresolved.push(`no free interior box for preset: ${label} (${prefix})`)
+      stats?.notes.push(`failed to place preset: ${label} (no free interior box ${String(blocksX)}x${String(blocksY)})`)
+      return false
+    }
     const { bx, by } = pos
     claimBox(bx, by, blocksX, blocksY, true)
     specialPresets.push({ name: piece.name, ds1, bx, by, blocksX, blocksY })
@@ -1900,7 +1926,11 @@ function planAct1OutdoorLevel(
    */
   const placeGraveyardPreset = (withGate: boolean): boolean => {
     const gyPiece = findPiece('Act 1 - Graveyard')
-    if (gyPiece?.levels[0] === undefined || gridWidth < 5 || gridHeight < 6) return false
+    if (gyPiece?.levels[0] === undefined || gridWidth < 5 || gridHeight < 6) {
+      stats?.unresolved.push('failed to place Graveyard preset')
+      stats?.notes.push('failed to place Graveyard preset (missing piece or grid too small)')
+      return false
+    }
     const ds1 = gyPiece.levels[0]
     claimBox(1, 1, 3, 4, true)
     specialPresets.push({ name: gyPiece.name, ds1, bx: 1, by: 1, blocksX: 3, blocksY: 4 })
@@ -1941,7 +1971,9 @@ function planAct1OutdoorLevel(
    */
   const placeInteriorPresets = (levelId: number): void => {
     if (levelId === 2) {
-      addInteriorPresetWithRoad('Act 1 - DOE Entrance', 'Den of Evil Entrance', undefined, 8)
+      if (!addInteriorPresetWithRoad('Act 1 - DOE Entrance', 'Den of Evil Entrance', undefined, 8)) {
+        stats?.notes.push('Den of Evil Entrance preset failed to place')
+      }
       const bivouac = findPiece('Act 1 - Bivouac') ?? findPiece('Act 1 - Cottages')
       if (bivouac?.levels[0] !== undefined) {
         const ds1 = bivouac.levels[0]
@@ -1951,28 +1983,52 @@ function planAct1OutdoorLevel(
         if (pos !== null) {
           claimBox(pos.bx, pos.by, w, h, true)
           specialPresets.push({ name: bivouac.name, ds1, bx: pos.bx, by: pos.by, blocksX: w, blocksY: h })
+        } else {
+          stats?.notes.push('Bivouac preset failed to place (no free box)')
         }
       }
     } else if (levelId === 3) {
-      addInteriorPresetWithRoad('Act 1 - Cave Entrance', 'Cave Level 1 Entrance', undefined, 9)
-      addInteriorPresetWithRoad('Act 1 - Bivouac', 'Bivouac Camp', 'south')
+      if (!addInteriorPresetWithRoad('Act 1 - Cave Entrance', 'Cave Level 1 Entrance', undefined, 9)) {
+        stats?.notes.push('Cave Level 1 Entrance preset failed to place')
+      }
+      if (!addInteriorPresetWithRoad('Act 1 - Bivouac', 'Bivouac Camp', 'south')) {
+        stats?.notes.push('Bivouac Camp preset failed to place')
+      }
     } else if (levelId === 4) {
-      addInteriorPresetWithRoad('Act 1 - Cairn Stones', 'Cairn Stones', 'south', 38)
-      addInteriorPresetWithRoad('Act 1 - Cave Entrance', 'Underground Passage Entrance', undefined, 10)
+      if (!addInteriorPresetWithRoad('Act 1 - Cairn Stones', 'Cairn Stones', 'south', 38)) {
+        stats?.notes.push('Cairn Stones preset failed to place')
+      }
+      if (!addInteriorPresetWithRoad('Act 1 - Cave Entrance', 'Underground Passage Entrance', undefined, 10)) {
+        stats?.notes.push('Underground Passage Entrance preset failed to place')
+      }
     } else if (levelId === 5) {
-      addInteriorPresetWithRoad('Act 1 - Inifus', 'Tree of Inifuss', 'south')
-      addInteriorPresetWithRoad('Act 1 - Cave Entrance', 'Underground Passage Exit', undefined, 10)
+      if (!addInteriorPresetWithRoad('Act 1 - Inifus', 'Tree of Inifuss', 'south')) {
+        stats?.notes.push('Tree of Inifuss preset failed to place')
+      }
+      if (!addInteriorPresetWithRoad('Act 1 - Cave Entrance', 'Underground Passage Exit', undefined, 10)) {
+        stats?.notes.push('Underground Passage Exit preset failed to place')
+      }
     } else if (levelId === 6) {
       // The Forgotten Tower is always beside one of the Black Marsh's roads,
       // never dropped on open ground, which is why it goes through the
       // road-joining path rather than the plain scatter.
-      addInteriorPresetWithRoad('Act 1 - Tower 1', 'Forgotten Tower', 'south', 20)
-      addInteriorPresetWithRoad('Act 1 - Cave Entrance', 'Hole Level 1 Entrance', undefined, 11)
+      if (!addInteriorPresetWithRoad('Act 1 - Tower 1', 'Forgotten Tower', 'south', 20)) {
+        stats?.notes.push('Forgotten Tower preset failed to place')
+      }
+      if (!addInteriorPresetWithRoad('Act 1 - Cave Entrance', 'Hole Level 1 Entrance', undefined, 11)) {
+        stats?.notes.push('Hole Level 1 Entrance preset failed to place')
+      }
     } else if (levelId === 7) {
-      addInteriorPresetWithRoad('Act 1 - Cave Entrance', 'Pit Level 1 Entrance', undefined, 12)
+      if (!addInteriorPresetWithRoad('Act 1 - Cave Entrance', 'Pit Level 1 Entrance', undefined, 12)) {
+        stats?.notes.push('Pit Level 1 Entrance preset failed to place')
+      }
     } else if (levelId === 39) {
-      addInteriorPresetWithRoad('Act 1 - Corral Fill', 'Cow Corral', 'south')
-      addInteriorPresetWithRoad('Act 1 - Bivouac', 'Cow Bivouac', 'east')
+      if (!addInteriorPresetWithRoad('Act 1 - Corral Fill', 'Cow Corral', 'south')) {
+        stats?.notes.push('Cow Corral preset failed to place')
+      }
+      if (!addInteriorPresetWithRoad('Act 1 - Bivouac', 'Cow Bivouac', 'east')) {
+        stats?.notes.push('Cow Bivouac preset failed to place')
+      }
     }
   }
 
@@ -1989,7 +2045,12 @@ function planAct1OutdoorLevel(
       if (placedTown && gate === townSeam) continue
       addBorderGate(SIDE_TO_EDGE[gate.side], gate.variant ?? 3, gate.label, gate.toLevelId)
     }
-    if (id === 17) placeGraveyardPreset(false)
+    if (id === 17) {
+      if (!placeGraveyardPreset(false)) {
+        stats?.unresolved.push('Burial Grounds Graveyard preset failed to place')
+        stats?.notes.push('Burial Grounds Graveyard preset failed to place')
+      }
+    }
     placeInteriorPresets(id)
   } else if (id === 2) {
     // Blood Moor: Town Transition + Exit Gate to Cold Plains + Den of Evil Entrance
@@ -2032,7 +2093,10 @@ function planAct1OutdoorLevel(
     placeInteriorPresets(7)
   } else if (id === 17) {
     // Burial Grounds (5x6 blocks): Graveyard preset (3x4 blocks at bx=1, by=1) + South Entry Gate
-    if (!placeGraveyardPreset(true)) addBorderGate('bottom', 4, 'Burial Grounds Gate', 3)
+    if (!placeGraveyardPreset(true)) {
+      stats?.notes.push('Burial Grounds Graveyard preset failed, falling back to border gate')
+      addBorderGate('bottom', 4, 'Burial Grounds Gate', 3)
+    }
   } else if (id === 39 || id === 46) {
     // Moo Moo Farm (39) & Canyon of the Magi (46): Closed border, no border gates
     if (id === 39) placeInteriorPresets(39)
@@ -4941,16 +5005,7 @@ export function generateWilderness(request: WildernessRequest): WildernessResult
   let floorLayers = 1
   let substitutionType = 0
   let version = 0
-  let inferredAct = 1
-  if (request.levelId >= 40 && request.levelId < 75) inferredAct = 2
-  else if (request.levelId >= 75 && request.levelId < 103) inferredAct = 3
-  else if (request.levelId >= 103 && request.levelId < 109) inferredAct = 4
-  else if (request.levelId >= 109) inferredAct = 5
-  else if (/Act 2/i.test(request.levelTypeName)) inferredAct = 2
-  else if (/Act 3/i.test(request.levelTypeName)) inferredAct = 3
-  else if (/Act 4/i.test(request.levelTypeName)) inferredAct = 4
-  else if (/Act 5/i.test(request.levelTypeName)) inferredAct = 5
-
+  const inferredAct = actOfLevel(request.levelId, request.levelTypeName)
   let act = inferredAct
   const allLevels: Ds1[] = []
   for (const piece of request.pieces) for (const level of piece.levels) allLevels.push(level)
@@ -5126,7 +5181,7 @@ export function generateWilderness(request: WildernessRequest): WildernessResult
   let act1Plan: Act1OutdoorPlan | undefined
   let dirtPathGrid: Uint8Array | undefined
   if (request.levelTypeName === 'Act 1 - Wilderness' || request.gates !== undefined) {
-    act1Plan = planAct1OutdoorLevel(request, gridWidth, gridHeight, rng)
+    act1Plan = planAct1OutdoorLevel(request, gridWidth, gridHeight, rng, stats)
     stats.anchors = act1Plan.anchors.length
     stats.entrances = toEntrances(act1Plan.anchors)
     const polylines = buildRoadNetworkPolylines(act1Plan, gridWidth, gridHeight, rng)
@@ -5149,6 +5204,7 @@ export function generateWilderness(request: WildernessRequest): WildernessResult
     request.levelId,
     act1Plan?.openGates,
     act1Plan?.claimedBorderBlocks,
+    request.gates,
   )
 
   // Step 4B: Stamp anchored special presets (Town Transition, Den of Evil, Cave Entrance, Cairn Stones, etc.)
diff --git a/tests/maze-special-passes.test.ts b/tests/maze-special-passes.test.ts
index 9931269..23f32ae 100644
--- a/tests/maze-special-passes.test.ts
+++ b/tests/maze-special-passes.test.ts
@@ -511,6 +511,33 @@ describe('Diablo II DRLG Maze Special Passes', () => {
       const specials = res.stats.specialsApplied as { room: number; kind: string; sides: string }[]
       expect(specials.some(s => s.kind === 'waypoint')).toBe(true)
     })
+
+    test('Halls of Pain (level 123): generates all 4 waypoint directions including NE across seeds', () => {
+      const pieces = createStandardPieceSet('Act 5 - Temple', templeExtraPieces)
+      const observedDirs = new Set<string>()
+
+      for (let seed = 1; seed <= 50; seed++) {
+        const res = generateMaze({
+          levelId: 123,
+          levelName: 'Halls of Pain',
+          sectionSize: 10,
+          minRooms: 5,
+          merge: 500,
+          seed,
+          pieces,
+        })
+        const specials = res.stats.specialsApplied as { room: number; kind: string; sides: string }[]
+        const wp = specials.find(s => s.kind === 'waypoint')
+        if (wp !== undefined) {
+          observedDirs.add(wp.sides)
+        }
+      }
+
+      expect(observedDirs).toContain('NE')
+      expect(observedDirs).toContain('NW')
+      expect(observedDirs).toContain('SW')
+      expect(observedDirs).toContain('SE')
+    })
   })
 
   /* ----------------------------------------------------------------------- *
diff --git a/tests/wilderness-features.test.ts b/tests/wilderness-features.test.ts
index a37a7d1..14f20f0 100644
--- a/tests/wilderness-features.test.ts
+++ b/tests/wilderness-features.test.ts
@@ -60,6 +60,29 @@ describe("Wilderness Features & Border Rules", () => {
     expect(bloodMoorOpenings.has("9,5")).toBe(true)
   })
 
+  test("getPerimeterOpenings defaults to open borders for Act 3 Jungles and outdoor levels", () => {
+    // Act 3: Spider Forest (76), Great Marsh (77), Flayer Jungle (78)
+    const spiderForestOpenings = getPerimeterOpenings(76, 10, 10)
+    expect(spiderForestOpenings.size).toBe(2)
+    expect(spiderForestOpenings.has("5,9")).toBe(true)
+    expect(spiderForestOpenings.has("9,5")).toBe(true)
+
+    // Act 5: Arreat Plateau (113)
+    const arreatOpenings = getPerimeterOpenings(113, 10, 10)
+    expect(arreatOpenings.size).toBe(2)
+  })
+
+  test("getPerimeterOpenings maps planned gates to perimeter block coordinates", () => {
+    const plannedGates = [
+      { side: 'north' as const, toLevelId: 75, label: 'To Town' },
+      { side: 'east' as const, toLevelId: 77, label: 'To Marsh' },
+    ]
+    const openings = getPerimeterOpenings(76, 12, 14, plannedGates)
+    expect(openings.size).toBe(2)
+    expect(openings.has("6,0")).toBe(true) // north: (12/2, 0)
+    expect(openings.has("11,7")).toBe(true) // east: (12-1, 14/2)
+  })
+
   test("selectBorderVariant picks open variant for openings and closed variant for closed walls", () => {
     const closedDs1 = makeMockDs1(8, 8, false)
     const openDs1 = makeMockDs1(8, 8, true)
@@ -356,4 +379,32 @@ describe("Wilderness Features & Border Rules", () => {
     expect(foundContinuousEW).toBe(true)
     expect(foundEndCapEW).toBe(true)
   })
+
+  test("records unresolved presets and notes when requested preset piece is missing", () => {
+    const borderDs1 = makeMockDs1(8, 8, false)
+    const piece: WildernessPiece = {
+      name: "Act 1 - Wild Border 1",
+      border: true,
+      levels: [borderDs1],
+    }
+
+    const result = generateWilderness({
+      levelId: 2,
+      levelName: "Blood Moor",
+      levelTypeName: "Act 1 - Wilderness",
+      sizeX: 80,
+      sizeY: 80,
+      subType: 0,
+      subTheme: 0,
+      seed: 9999,
+      pieces: [piece], // Missing Den of Evil Entrance preset!
+      substitutions: [],
+    })
+
+    const unresolved = result.stats.unresolved as string[]
+    const notes = result.stats.notes as string[]
+    expect(unresolved.length).toBeGreaterThan(0)
+    expect(unresolved.some((u: string) => u.includes('Act 1 - DOE Entrance'))).toBe(true)
+    expect(notes.some((n: string) => n.includes('Den of Evil Entrance'))).toBe(true)
+  })
 })
diff --git a/tests/world-graph.test.ts b/tests/world-graph.test.ts
index 55ce4f9..458445f 100644
--- a/tests/world-graph.test.ts
+++ b/tests/world-graph.test.ts
@@ -1,5 +1,7 @@
 import { describe, it, expect } from 'vitest'
 import type { D2Table } from '../src/game/acts.ts'
+import { ACT_TOWNS, townLevelForAct } from '../src/game/acts.ts'
+import { actOfLevel } from '../src/game/wilderness.ts'
 import {
   parseLevelRows,
   buildWorldGraph,
@@ -16,6 +18,11 @@ import {
   DROPPED_VIS_EDGES,
 } from '../src/game/world-graph.ts'
 import type { Side } from '../src/game/world-graph.ts'
+import {
+  seamArrivalSpot,
+  SEAM_TRIGGER_SUBTILES,
+  type LinkGrid,
+} from '../src/game/level-links.ts'
 
 /**
  * Build a `Levels.txt`-shaped table from sparse overrides.
@@ -376,3 +383,100 @@ describe('parseWarpGeometry', () => {
     expect(findWarpGeometry(parseWarpGeometry(lvlwarp), 71)?.id).toBe(71)
   })
 })
+
+describe('seamArrivalSpot', () => {
+  function makeGrid(width: number, height: number, blockedIndices: Set<number> = new Set()): LinkGrid {
+    const blocked = new Uint8Array(width * height)
+    for (const idx of blockedIndices) {
+      blocked[idx] = 1
+    }
+    return {
+      cellsX: Math.ceil(width / 5),
+      cellsY: Math.ceil(height / 5),
+      gridWidth: width,
+      gridHeight: height,
+      blocked,
+    }
+  }
+
+  it('places arrival strictly outside trigger box on all 4 sides', () => {
+    const grid = makeGrid(50, 50)
+    const sides: Side[] = ['north', 'south', 'east', 'west']
+    const x = 25
+    const y = 25
+
+    for (const side of sides) {
+      const spot = seamArrivalSpot(grid, x, y, side)
+      const insideTriggerBox =
+        Math.abs(spot.x - x) <= SEAM_TRIGGER_SUBTILES &&
+        Math.abs(spot.y - y) <= SEAM_TRIGGER_SUBTILES
+      expect(insideTriggerBox).toBe(false)
+      expect(spot).not.toEqual({ x, y })
+    }
+  })
+
+  it('never bounces back to trigger tile (x, y) even when completely blocked', () => {
+    // A grid where every single tile is impassable
+    const blockedSet = new Set<number>()
+    for (let i = 0; i < 50 * 50; i++) blockedSet.add(i)
+    const grid = makeGrid(50, 50, blockedSet)
+
+    const spot = seamArrivalSpot(grid, 20, 0, 'north')
+    // Must never fall back to trigger tile (20, 0)
+    expect(spot).not.toEqual({ x: 20, y: 0 })
+    const insideTriggerBox =
+      Math.abs(spot.x - 20) <= SEAM_TRIGGER_SUBTILES &&
+      Math.abs(spot.y - 0) <= SEAM_TRIGGER_SUBTILES
+    expect(insideTriggerBox).toBe(false)
+  })
+
+  it('ignores walkable tiles inside trigger radius and finds the nearest valid tile outside', () => {
+    // Only the trigger tile itself and its immediate neighbors (radius 2) are walkable
+    const blockedSet = new Set<number>()
+    for (let i = 0; i < 50 * 50; i++) blockedSet.add(i)
+    // Clear trigger tile and one tile far inward
+    blockedSet.delete(0 * 50 + 20) // trigger (20, 0)
+    blockedSet.delete(1 * 50 + 20) // (20, 1) inside trigger box
+    blockedSet.delete(10 * 50 + 20) // (20, 10) valid outside trigger box
+
+    const grid = makeGrid(50, 50, blockedSet)
+    const spot = seamArrivalSpot(grid, 20, 0, 'north')
+
+    expect(spot).toEqual({ x: 20, y: 10 })
+    expect(Math.abs(spot.y - 0)).toBeGreaterThan(SEAM_TRIGGER_SUBTILES)
+  })
+})
+
+describe('ACT_TOWNS and townLevelForAct single source of truth', () => {
+  it('defines the correct canonical town level IDs for Acts 1..5', () => {
+    expect(ACT_TOWNS).toEqual([1, 40, 75, 103, 109])
+  })
+
+  it('resolves townLevelForAct for all 5 acts correctly', () => {
+    expect(townLevelForAct(1)).toBe(1)
+    expect(townLevelForAct(2)).toBe(40)
+    expect(townLevelForAct(3)).toBe(75)
+    expect(townLevelForAct(4)).toBe(103)
+    expect(townLevelForAct(5)).toBe(109)
+  })
+
+  it('handles boundary / out-of-range acts gracefully', () => {
+    expect(townLevelForAct(0)).toBe(1)
+    expect(townLevelForAct(-5)).toBe(1)
+    expect(townLevelForAct(6)).toBe(109)
+    expect(townLevelForAct(99)).toBe(109)
+  })
+
+  it('actOfLevel correctly partitions level IDs matching ACT_TOWNS', () => {
+    expect(actOfLevel(1)).toBe(1)
+    expect(actOfLevel(39)).toBe(1)
+    expect(actOfLevel(40)).toBe(2)
+    expect(actOfLevel(74)).toBe(2)
+    expect(actOfLevel(75)).toBe(3)
+    expect(actOfLevel(102)).toBe(3)
+    expect(actOfLevel(103)).toBe(4)
+    expect(actOfLevel(108)).toBe(4)
+    expect(actOfLevel(109)).toBe(5)
+    expect(actOfLevel(136)).toBe(5)
+  })
+})