Skip to main content
Chimera is the update to Halo: Combat Evolved for the PC that we should have had but never got. It provides extensive fixes, enhancements, and features while preserving the base game experience.

​
What is Chimera?

Chimera is a comprehensive mod for Halo: Combat Evolved PC that fixes bugs, adds quality-of-life improvements, and enhances the game with modern features. Most features are opt-in to ensure the base game is preserved as much as possible.
Chimera works by replacing the game’s strings.dll file, making installation simple and reversible.

​
Key Features

Chimera provides numerous enhancements across several categories:

​
Passive Features (Always On)

  • Interpolation: Smooth object movement beyond 30 FPS
  • Increased Limits: BSP polygon limit boosted to 32,767, visible objects to 1,024, draw distance to ~6.86 km
  • Compressed Maps: Support for zstd-compressed map files
  • Fast Loading: CRC32 verification only when loading maps, not at startup
  • High FPS Fixes: Camera shake, checkpoints, contrails, motion sensor, and auto-centering all work correctly at high frame rates
  • Shader Fixes: Restores Xbox-accurate rendering, fixes many Gearbox regressions
  • Visual Fixes: FOV consistency, model LOD, sun flares, zoom blur, multitexture overlays, z-fighting reduction

​
Optional Features

  • Custom Field of View: Adjust FOV with vertical FOV locking for aspect ratio consistency
  • Widescreen Support: Proper HUD scaling for ultrawide displays
  • Mouse Enhancements: Disable mouse acceleration, granular sensitivity control
  • Lua Scripting: Load custom scripts globally or per-map
  • Map Downloading: Automatic map downloads from HAC2 repository when joining servers
  • Custom Chat: Improved chat system with customizable colors and positioning
  • Devmode: Enable developer commands without blocking multiplayer
Chimera includes over 70 commands for customization:
  • chimera_fov - Set field of view
  • chimera_block_mouse_acceleration - Disable mouse acceleration
  • chimera_show_fps - Display FPS counter
  • chimera_widescreen_fix - Fix HUD scaling for widescreen
  • chimera_interpolate - Toggle interpolation
  • And many more…
See the full command reference for details.

​
System Requirements

​
Minimum Requirements

Operating System:
  • Windows 7 or later (recommended)
  • Windows XP or later (using dedicated Windows XP release)
  • Linux with Wine 4.0 or newer
Game Version:
  • Halo: Combat Evolved PC version 1.10
  • OR Halo Custom Edition (any version)
  • OR Halo Trial
Chimera requires Halo PC version 1.10. Make sure to update your game before installing.
For optimal performance with all features enabled:
  • CPU: Intel Core i3-2100 (3.1 GHz) or AMD FX 6100 (3.3 GHz) or better
  • RAM: 8 GB or more (for map caching features)
  • GPU: NVIDIA GeForce 8500 GT, ATI Radeon HD 5670, or better
While Chimera isn’t demanding, some features like interpolation and increased limits may impact performance on very old hardware.

​
Custom Edition Support on Retail

Chimera enables Custom Edition map support on retail Halo PC. To use this feature:
  1. Obtain the Custom Edition resource maps (bitmaps.map, loc.map, sounds.map)
  2. Rename them with the custom_ prefix
  3. Place them in your maps folder
This allows you to play Custom Edition maps without installing Halo Custom Edition separately.

​
Mod Support

Chimera supports loading binary mods (DLL files) from a mods folder in your game directory.
Chimera does not support HAC2 or Open Sauce due to conflicts. These mods modify the game in similar ways and cannot run together.

​
License

Chimera is licensed under GNU General Public License version 3.0 (GPL-3.0).
  • Free and open source software
  • You can redistribute and modify under GPL-3.0 terms
  • No warranty provided
  • Source code available at github.com/SnowyMouse/chimera
To use Chimera under a different license, you would need permission from all contributors.

​
What’s Next?

Ready to install Chimera? Check out the Installation Guide for step-by-step instructions. Once installed, see the Quick Start Guide to begin using Chimera’s features.

Build docs developers (and LLMs) love

Get started for freeTalk to us