Arcane Tycoon — Heroes & Magic theme park tycoon game

Complete browser game inspired by OpenRCT2 with fantasy twist:
- Custom roller coaster designer with physics-based ratings + on-ride POV
- 10 animated rides, 7 shops, 16 scenery items, path network & guest AI
- Heroes guild vs monster invasions (5 classes, XP/gear/bosses)
- Magic spell system (8 spells), research tree, economy/marketing/loans
- Day-night cycle, weather, park rating, awards, 4 scenarios
- Save/load slots + autosave, procedural WebAudio SFX/music
- Isometric canvas renderer, minimap, diagnostics overlay
- Test suites: smoke(13), linkcheck, inputcheck, framecheck, rendercheck, flow

js/game/save.js

@@ -0,0 +1,78 @@
+// ============ save.js — localStorage slots, autosave, export/import ============
+import { serialize, deserialize } from '../game/state.js';
+import { download } from '../core/util.js';
+
+const KEY = 'arcane_tycoon_save_';
+const SLOTS = ['auto', 'slot1', 'slot2', 'slot3'];
+
+export function listSaves() {
+  const out = [];
+  for (const s of SLOTS) {
+    try {
+      const raw = localStorage.getItem(KEY + s);
+      if (!raw) { out.push({ slot: s, exists: false }); continue; }
+      const d = JSON.parse(raw);
+      out.push({
+        slot: s, exists: true,
+        parkName: d.park?.name || 'Park',
+        scenario: d.scenario,
+        date: `Y${d.time?.year} M${(d.time?.month ?? 0) + 1}`,
+        cash: d.cash,
+        guests: d.guests?.length ?? 0,
+        savedAt: d.savedAt,
+      });
+    } catch {
+      out.push({ slot: s, exists: false });
+    }
+  }
+  return out;
+}
+
+export function saveTo(state, slot) {
+  const data = serialize(state);
+  data.savedAt = Date.now();
+  try {
+    localStorage.setItem(KEY + slot, JSON.stringify(data));
+    return true;
+  } catch (e) {
+    console.error('save failed', e);
+    return false;
+  }
+}
+
+export function loadFrom(slot) {
+  try {
+    const raw = localStorage.getItem(KEY + slot);
+    if (!raw) return null;
+    return deserialize(JSON.parse(raw));
+  } catch (e) {
+    console.error('load failed', e);
+    return null;
+  }
+}
+
+export function hasAutosave() {
+  try { return !!localStorage.getItem(KEY + 'auto'); } catch { return false; }
+}
+
+export function autosave(state) {
+  return saveTo(state, 'auto');
+}
+
+export function exportSave(state) {
+  const data = serialize(state);
+  data.savedAt = Date.now();
+  const name = (state.park.name || 'park').replace(/\W+/g, '_').toLowerCase();
+  download(`arcane-tycoon-${name}.json`, JSON.stringify(data));
+}
+
+export function importSaveText(text) {
+  try {
+    const data = JSON.parse(text);
+    if (!data.version) throw new Error('Not an Arcane Tycoon save');
+    return deserialize(data);
+  } catch (e) {
+    console.error('import failed', e);
+    return null;
+  }
+}