Sébastien QUEROLandClaude Opus 5.5
e00dfab42e
Map trainers run the ROM's TalkToTrainerScript and SeenByTrainerScript. _CheckTrainerBattle runs before tile events at the end of each step and on idle ticks; TrainerWalkToPlayer builds wMovementBuffer natively, and writeobjectxy keeps the trainer where it stopped. The interpreter gains the trainer header commands, wRunningTrainerBattleScript and hidden items (HiddenItemScript). Trainers with several Pokémon send out the next one through EnemyPartyMonEntrance and FindMonInOTPartyToSwitchIntoBattle, including its BattleRandom fallback. AI_SwitchOrTryItem, CheckAbleToSwitch and AI_Switch are translated with their original bugs, and wPlayerUsedMoves is recorded. The Shift-mode switch offer, trainer items, Pursuit on a switch, Perish Song and Spikes remain refused. Route 30 and its Berry house are enabled; Mr. Pokémon's house and Route 31 stay closed. A refused trainer sighting does not restart until the player moves, so a rollback cannot trap the player in view. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Crystal
A native web port of Pokémon Crystal, translated from PRET's Game Boy disassembly. The game runs in TypeScript and reads graphics, maps, sprites and dialogue from the user's own ROM. No original game assets are included.
Current milestone: from the opening to Route 30. Play in a minimal Crystal-style interface with Game, Savegames, Map, Pokédex, Link and Friends tabs. The native canvas fills the play area, and the live local map follows your position. Save, export and import work now. Pokédex, Link and Friends show their planned scope without placeholder data.
Walk around your home, the town and its buildings at the original walking speed. Mom gives you the Pokégear and asks the day of the week. The teacher stops you from leaving town. Your rival shoves you away from the lab window. Professor Elm introduces his errand, and you choose Chikorita, Cyndaquil or Totodile. The Pokémon's picture and stats come from your ROM, and you can nickname it. Elm's aide then gives you a Potion. These scenes run the game's own event scripts and movement data, with native choices and naming.
With a Pokémon, head west along Route 29 to Cherrygrove City. Wild Pokémon appear in the grass and battle you with their original moves. The route has ledges, signs, an item ball and a Berry tree that regrows daily. Townspeople wander and look around as in the original. In Cherrygrove, the Guide Gent gives a tour, the Poké Mart buys and sells items, the Pokémon Center nurse heals your party, and a whiteout returns you to the last Pokémon Center you entered.
North of Cherrygrove, Route 30's trainers battle you. Bug Catcher Don spots you from a distance and walks over; Youngster Mikey battles when you talk to him. Each sends out two Pokémon, and beaten trainers remember you. The Berry house gives a Berry, and a Potion is hidden on the route.
Catching, Mr. Pokémon's house and the Mystery Egg errand, Route 31 and beyond, party and bag menus, decorations and audio are still being ported. Unported neighboring areas appear at the edges but cannot be entered yet.
Run
Requires Node.js 22.12 or newer.
npm ci
npm run dev
Open the printed local URL, choose a name/character and select your uncompressed English US/Europe revision 1.1 ROM (.gbc, 2 MiB). Its checksum is verified locally. ROMs are never uploaded or stored in browser storage; select yours again after reloading to resume.
Use onscreen controls, or focus the game screen and use arrows to move, X to interact and X / Z to continue dialogue. In choices, Up / Down change the answer, X confirms and Z answers No. Sessions save every 10 seconds and when paused. Switching apps pauses play. Download a backup before clearing browser data.
Native saves are separate from emulator snapshots and cartridge .sav files. Saving during a scene keeps the progress from before it, so the scene replays after loading. Time of day follows the device clock; the weekday you give Mom is kept as an offset from the device's weekday. The tile counter measures in-game movement, not real-world steps.
Reference emulator
During development, open /reference.html to run the original game for comparison. It has separate saves and does not run inside the native player. Reference tools and the emulator are excluded from the default build.
npm run build # Native application in dist/
npm run check:release # Check the native distribution
npm run build:reference # Optional reference in dist-reference/
Serve dist/ through an HTTPS static host, or use npm run preview locally. Subdirectory hosting is supported with npm run build -- --base=/Crystal/. Use HTTPS from another device; ROM verification and save locking require a secure context.
Development
npm test
npx playwright install chromium webkit
npm run test:e2e
npm run check:vendor
Local-ROM tests use Pokemon - Crystal Version (UE) (V1.1) [C][!].gbc at the root, or CRYSTAL_ROM_PATH. They skip when absent; no test downloads a ROM. Game files, private reference builds and gameplay screenshots must remain ignored.
The full port plan covers remaining game systems, save slots, the world map, Pokédex, internet Link, friends and optional mobile step support for egg hatching. See the architecture and routine map and verification for module boundaries and reference checks.
References: PRET documentation, wiki and source. The development reference uses binjgb under its MIT license; see provenance.
Independent project. Not affiliated with Nintendo or Game Freak.