Chimera Runtime

Chimera Runtime

Build your own game out of the games you own. Pick the maps, the moves, the weapons and the rules you like from every game on your shelf, load in, and play them together.

Chimera runs on IW4L, a from-scratch Rust rewrite of Modern Warfare 2, and grew out of the 2010 Rust Rewrite Mashup that put Skate 3 and Minecraft into it. Everything since then is a pack: one whole game — its maps, weapons, characters, sounds and mechanics — unlocked by your own copy of that game.

The idea

• Every game is a pack, and a pack needs your copy. Chimera checks your

  install (or ROM) and reads what it needs from it on your machine. Nothing from any game is in this repo, and nothing is downloaded from anywhere else.

• Every pack brings the whole game. The aim for each one is everything

  it has: every map playable, every weapon, character, sound and mechanic. Packs fill in one importer at a time; docs/PACKS.md shows how far each has got.

• Any map, any game, any mix. Halo shields on Counter-Strike's Dust 2.

  Titanfall wall-running through Quake's E1M1. Bloodborne trick weapons and RDR2's Dead Eye on a Skate 3 district. Skyrim's swords and shout in an MW2 match.

• Set it up, then play. Press F1 in game for the setup panel: pick a

  preset or tick rules one by one. Locked rules tell you which game unlocks them.

• Built by everyone. The repo is public. Packs are written by the

  community, reviewed by maintainers, and documented with where every number came from. See Contributing.

• Multiplayer, one day. A match already turns away a player whose rules

  differ from the host's; the plan is that each player brings their own copies, as Skyrim Together and Elden Ring's co-op mods do.

What's in it

Every pack, its controls and its rules: docs/PACKS.md. What was researched for each game and from where: docs/GAME-RESEARCH.md.

Getting started

1. Grab the zip from Releases and extract it

   somewhere you can write to (not Program Files), or build it yourself (docs/BUILD.md).

2. Double-click iw4l.exe and confirm your MW2 folder. It asks whether you

   have Skate 3: choose Yes and select your default.xex, or No.

3. Unlock your other games: run chimera-donor packs. It looks through your

   Steam libraries and checks each game it finds; point it at anything else with chimera-donor packs --pack --game.

4. Start a match, press F1, pick what to play with, and map_restart.

   Quake, Half-Life and Source maps sit in the map list under their own tabs.

Controls

Mario 64 moves come from jump and crouch, wall-running from running along a wall, sliding from crouching while sprinting. Rebind anything with bind +dodge (+grapple, +lockon, +shout, +guard, +weaponwheel, +focus). The console (`) has packs, rules, moves and setup.

The Minecraft map

• Minecraft's own world generation, day and night, sky, clouds and lighting, which also falls on your gun.
• Vanilla mobs, passive and hostile; shoot them and they fight back.
• Shoot blocks to break them, scaled by each gun's real MW2 damage and range. Grenades blow up like TNT.
• An inventory and hotbar in MW2's look; place blocks, mine and punch with your bare MW2 hands.
• Play it from Create Game → Minecraft → overworld, or map minecraft:overworld.

The first start downloads Minecraft 26.3's files (about 125 MB) from Mojang's servers, as the launcher does, into iw4l-artifacts/minecraft-26.3. More in the map's controls: E inventory, Q drop, 1–9 hotbar.

Controller

Plug in a controller and play; the game follows whichever controller you last touched. Options → Controller has MW2's console layouts, sensitivity, aim assist (Standard and Full, as on console) and deadzones; Options → Controls rebinds keys and buttons.

Contributing

Adding a game is the heart of this project. A pack is:

1. Research — a row in docs/GAME-RESEARCH.md:

   how the player's copy is recognised, what is read from it, every number with its source.

2. The copy check — a case in crates/donor_import/src/packs.rs

   (published checksums, the install's own files and headers).

3. Rules — the pack and its rules in crates/mechanics/src/rules.rs,

   deterministic logic in crates/mechanics, the hook in crates/sim.

4. Content — an importer that reads the player's files (see the

   readers in crates/bsp_level and crates/donor_import/src/skyrim.rs). chimera-donor inspect runs every reader over a real copy and shows what reads and what does not.

5. Checks — what to try in game, in

   docs/MECHANICS-CHECKS.md.

The ground rules:

• Never commit anything from a game, converted or not, and never link to

  copies of games. Everything is read from the player's own copy.

• Read decompilations, GPL and unlicensed code for facts only; never copy

  it. MIT and similar work may lend ideas, credited in NOTICE.

• Keep TickInput -> sim::step -> Snapshot the only way game state changes,

  so prediction, replays and multiplayer keep working.

Open an issue to propose a pack, or a pull request when it plays. The docs/ folder (INDEX) explains how the engine fits together.

What's next

• A setup screen before you load in, not only in game.
• The rest of every game: more maps (Skyrim and Fallout cells, CS2's own

  maps, Kingdom Come's regions, Doom, Halo, Souls), models and sounds in game for every pack (Source MDL, Skyrim NIF and KCD2 meshes are read already), Cyberpunk's resources, Unity and Unreal games, Elden Ring and Fallout weapons.

• Packs sharing their rules with the other players in a match, so friends

  can each bring their games.

Known issues

• If you die in skater mode, bodies pile up.
• The skateboard is invisible on some maps.
• Bots on Skate 3 districts and imported levels still follow MW2 routes.

Credits

• IW4L by vladtrc and contributors: the MW2 rewrite everything runs on (Apache-2.0, see NOTICE).
• 2010 Rust Rewrite Mashup by chasmlol: Skate 3 and Minecraft in IW4L.
• MinecraftOSS: the Rust Minecraft engine behind the world.
• SoulsFormats, DSAnimStudio and WolvenKit: read for file formats and how the games describe their weapons and wounds (see NOTICE).
• The communities whose research the packs stand on, listed with each pack in docs/GAME-RESEARCH.md.
• Every game named here belongs to its owners. You need your own copies; this project isn't affiliated with any of them.