COSOM · MONSTER WORLD IVDevelopment journal

COSOM · PRESERVATION JOURNAL

Monster World IV: the game, its pixels and its sound

· Version 0.1.0

The supplied English-modified Genesis cartridge, recovered music and effects, a zoomable graphics archive, and a browser player with a route guide, portable saves and optional assists.

Play the original · Music · Sound effects · Images and zoom

What is available

  • A self-hosted original-cartridge player preserves the supplied ROM bytes. The exact English translation/patch revision is unresolved and is identified by its SHA-256.
  • A left-side Route/Completed checklist contains 79 stable manual objectives across 13 story chapters, with separate checklist storage.
  • Hover/focus quick save and quick load use verified browser checkpoints. Startup Create/Load sessions use game/core-bound portable files carrying the native snapshot and full cartridge SRAM.
  • Changed, complete original Sage save records can update an already writable selected file. Read-only and download modes never pretend to overwrite a file or open automatic permission prompts.
  • Forward speed choices of 2x, 4x and 8x, and rewind choices of 0.5x, 1x, 2x, 4x and 8x use the pinned core and a bounded copied history that includes SRAM. Loading or starting a new session clears abandoned history.
  • Independent Infinite HP and enemy-contact invincibility, plus Add 5,000 / 50,000 / 100,000 gold buttons capped at the native 999,999 limit. The game has no spendable magic or experience-level meter.
  • The image gallery contains 1,847 entries: 1,128 indexed graphics banks with 36,096 patterns, glyphs, five native contexts, 351 direct-art load ranges and 339 mapped character contexts, including 184 Asha frames. Zoom, pan, palette previews, filters and downloads make their pixels inspectable.
  • The audio archive preserves 32 musical pieces (23 looping, nine finite), 49 effects (one native loop), and the original sound bank. Music introductions play once before repeating the verified native phrase. Lossless downloads remain separate from playback seam correction.

Verification

  • All 1,128 indexed graphics banks were byte-compared against execution of the original 68000 decompressor. Integrity checks cover 1,847 PNGs and 14,318 native sprite pixels. Direct-art evidence executes all 350 resolver IDs and verifies exact source/mapping slices, 290,848 composed frame pixels and 286,208 direct-bank pixels; one assembled Asha frame matches all 1,024 native VDP pixels.
  • All 83 original sound-test commands were captured: 81 audible entries and two verified-silent stop commands. Independent checks decoded 162 audio files and verified 24 loop recurrences; 23 focused audio-player assertions pass.
  • The actual pinned Genesis WASM passed full serializer, atomic state/SRAM restoration, failed recovery blocking, native cheat instruction/behavior fixtures and one-shot gold checks without changing the cartridge.
  • After a private original-debug warp fixture, genuine Sage dialogue, Yes and jar inputs saved both original slots, repeated a save and canceled without writing. Original Restart/Continue loaded distinct 5,000 and 10,000 gold records.
  • Actual browser checks covered startup, gameplay, Sage save detection, real portable downloads, quick restoration of gold, paused redraw, fresh-page restore, clean New sessions, route/completed reversal, music looping, finite endings and effect repeat.
  • File-owner tests reject wrong game/core/version, corruption, external edits, locked writers, failed close/readback and unsafe Save as targets. Confirmation follows exclusive write, completed close and full readback.
  • Privacy and scoped package gates keep research RAM/states, generated QA saves, credentials and local session data out of the public payload.
  • Actual selected-file Chrome QA passed for new files, same-file updates, Save as, explicit single-file update permission, original Sage automatic updates and reopened-page restoration. The exact final OS envelope also passed original native Restart/Continue with 10,000 gold, save point 49 and HP 3. Automatic saving resumes prior play while 13 callback race cases preserve deliberate pauses and failures; no human save files were touched.

Limits and remaining work

  • This is the supplied English-modified cartridge through Genesis emulation. Its exact translation/patch authorship remains unresolved; it is not presented as a verified clean Japanese retail image or a native game reconstruction.
  • Graphics-table coverage is complete and the verified direct-art ranges and mapped contexts extend character coverage. Other sprite animation mappings, every scene palette, raster effects and full level maps remain unresolved. Palette reference previews and sampled native contexts do not establish all game artwork.
  • The 79 story objectives are manual. A full campaign and physical wireless controller have not been tested. Enemy-contact suppression has native routine-fixture proof; natural enemy encounters across every stage have not been tested.
  • Only changed, stable, checksum-complete original save records trigger automatic file updates. Repeating an identical-byte Save is not detected by this read-only observer; Save session now is always available.
  • Rewind keeps approximately 15 seconds at ordinary speed, with positions quantized by capture intervals. Forward targets depend on device performance.
  • Playback loop boundaries derive from original sequence-state recurrence at native frame boundaries. A 3 ms WebAudio-only seam adjustment reduces discontinuity; lossless source captures are unchanged.

The supplied cartridge and original media remain preserved with source hashes. Optional browser controls are preservation enhancements. This article records this website release on its actual publication date.