v1.0.2 — Audio & stability fixes

OpenChaos v1.0.2 — Audio & stability fixes

Unofficial modernization of Urban Chaos (1999). Requires original game files (Steam/GOG).

What's new

Audio:

• Fixed level music stopping after the first track instead of playing continuously (sprint / stealth / combat music now loops as intended) — reported by Nervnobolnoj_beton (4c65f5e8)
• Fixed music fading out far too quickly when an action ends — the fade is now smooth and frame-rate independent (4c65f5e8)
• Fixed 3D positional sounds (fire, sirens, etc.) not attenuating naturally with distance — they now fade with distance like in the original (8e04accd)
• Fixed ambient events (sirens, thunder, animals) and the indoor/outdoor sound crossfade running too fast at high frame rates (95ed38fa)

Stability:

• Fixed a crash in the "The Fallen" mission that occurred after talking to a certain NPC — reported by Nervnobolnoj_beton (e6d5d8dc)
• Internal assertion failures no longer crash release builds — the game keeps running, shows a brief on-screen notice, and writes the details to a log file (e6d5d8dc)

Internal:

• Dialogue/cutscene voice waiting no longer busy-spins the CPU (4c21734b)

How to run

1. Download the zip for your platform
2. Extract into your Urban Chaos game folder (where the data folder is)
3. Run OpenChaos.exe (Windows), OpenChaos.command (macOS), or OpenChaos.sh (Linux)

Requirements

• Original Urban Chaos game files (Steam or GOG version)
• Windows 10+ (x64), macOS 12+ (Apple Silicon), or Linux x86_64 (Steam Deck compatible)

v1.0.1 — Bug fixes

OpenChaos v1.0.1 — Bug fixes

Unofficial modernization of Urban Chaos (1999). Requires original game files (Steam/GOG).

A small patch release on top of v1.0.0 — minor fixes, mostly making custom (non-campaign) maps open correctly, plus a couple of other small fixes.

What's new

Custom maps:

• Fixed custom (non-campaign) maps failing to open. This includes maps that ship loose .tga textures instead of a packed bundle — such textures now load and take priority over the bundle (so a custom map's own textures/skins are used). Also fixed opening these maps on Linux (f41b581e, faa6541d, 4dd9db74)

Other fixes:

• Fixed alpha-sorting of semi-transparent environment-mapped surfaces (e6d0fab1)
• Fixed mouse input not working in some cases (reported by PCambraia) (6fd71b5b)

How OpenChaos differs from the original

Full lists of how OpenChaos differs from the retail Urban Chaos:

• Gameplay (controls, camera, combat, vehicles, cheats, mechanics) — GAMEPLAY_CHANGES.md
• Technical (OpenGL renderer, 64-bit, cross-platform, unlocked frame rate, new audio/video backends) — TECHNICAL_CHANGES.md

How to run

1. Download the zip for your platform
2. Extract into your Urban Chaos game folder (where the data folder is)
3. Run OpenChaos.exe (Windows), OpenChaos.command (macOS), or OpenChaos.sh (Linux)

Requirements

• Original Urban Chaos game files (Steam or GOG) — any language works
• Windows 10+ (x64), macOS 12+ (Apple Silicon), or Linux x86_64 (Steam Deck compatible)

v1.0.0 — First stable release

OpenChaos v1.0.0 — First stable release

Unofficial modernization of Urban Chaos (1999). Requires original game files (Steam/GOG).

The first stable release. OpenChaos is the same Urban Chaos — not a remake — now fully playable start to finish on Windows, macOS (Apple Silicon) and Linux (Steam Deck), with reworked controls, gamepad support (Xbox and DualSense), any screen resolution, and a heavily modernized engine. No critical bugs; a few minor ones remain.

How OpenChaos differs from the original

Full lists of how OpenChaos differs from the retail Urban Chaos:

• Gameplay (controls, camera, combat, vehicles, cheats, mechanics) — GAMEPLAY_CHANGES.md
• Technical (OpenGL renderer, 64-bit, cross-platform, unlocked frame rate, new audio/video backends) — TECHNICAL_CHANGES.md

How to run

1. Download the zip for your platform
2. Extract into your Urban Chaos game folder (where the data folder is)
3. Run OpenChaos.exe (Windows), OpenChaos.command (macOS), or OpenChaos.sh (Linux)

Requirements

• Original Urban Chaos game files (Steam or GOG) — any language works
• Windows 10+ (x64), macOS 12+ (Apple Silicon), or Linux x86_64 (Steam Deck compatible)

v0.2.1 — Linux / Steam Deck support

OpenChaos v0.2.1 — Linux / Steam Deck support

Fan modernization of Urban Chaos (1999). Requires original game files (Steam/GOG).

What's new

• Added Linux x64 support — fully playable on Steam Deck, gamepad works (native controller and DualSense tested) (0ab1f8d1, 106c35b0, 20b51319)

Current state

This is an early alpha. The game launches and is partially playable, but expect:

• Crashes (especially on Windows)
• Visual glitches
• Fixed window resolution (no resize yet)
• No launcher or settings UI

How to run

1. Download the zip for your platform
2. Extract into your Urban Chaos game folder (where the data folder is)
3. Run OpenChaos.exe (Windows), OpenChaos.command (macOS), or OpenChaos.sh (Linux)

Requirements

• Original Urban Chaos game files (Steam or GOG version)
• Windows 10+ (x64), macOS 12+ (Apple Silicon), or Linux x86_64 (Steam Deck compatible)

v0.2.0 — Rendering fixes

OpenChaos v0.2.0 — Rendering fixes

Fan modernization of Urban Chaos (1999). Requires original game files (Steam/GOG).

What's new

Gameplay:

• Added gamepad cheats (see GAMEPLAY_CHANGES.md for details, document is in Russian) (0761e512)
• Grenade trajectory line is no longer shown during normal gameplay, moved to debug mode only (76bd738d)
• Shooting trace lines are no longer shown during normal gameplay, moved to debug mode only (0a315140)

Rendering bug fixes:

• Fixed transparent effects (fire, lights, steam) — leaves and other objects were incorrectly rendering on top of effects (b0511300)
• Fixed steam disappearing (22913158, d41caa97)
• Fixed puddles disappearing (9c0582ce)
• Fixed broken leaf/newspaper textures (6f175570)
• Fixed corrupted backgrounds for menu fonts and weapon icons ("ghost RGB" issue) (a01507a8)
• Fixed outro text background not being transparent (24f36fae)
• Fixed outro 3D models disappearing (64-bit regression) (d0198ff3)
• Fixed fog not being applied to people/characters (17e50da8)
• Fixed geometry polygons disappearing at the near clipping plane (2e5f8e17)
• Fixed D3D→OpenGL texturing convention issues (6fedfdfa)
• Fixed sound picker disappearing (c234a13a)
• Small lighting fix (1d7860e2)

Internal:

• Legacy Direct3D 6 backend is no longer supported and has been removed from the codebase (0888cd0d)

Current state

This is an early alpha. The game launches and is partially playable, but expect:

• Crashes (especially on Windows)
• Visual glitches
• Fixed window resolution (no resize yet)
• No launcher or settings UI

How to run

1. Download the zip for your platform
2. Extract into your Urban Chaos game folder (where the data folder is)
3. Run OpenChaos.exe (Windows) or OpenChaos.command (macOS)

Requirements

• Original Urban Chaos game files (Steam or GOG version)
• Windows 10+ (x64) or macOS 12+ (Apple Silicon)

v0.1.0 — First Alpha

OpenChaos v0.1.0 — First Alpha

Fan modernization of Urban Chaos (1999). Requires original game files (Steam/GOG).

What's new

• OpenGL renderer (replaces DirectX 6)
• Cross-platform: Windows x64, macOS ARM64
• DualSense / Xbox controller support

Current state

This is an early alpha. The game launches and is partially playable, but expect:

• Crashes (especially on Windows)
• Visual glitches
• Fixed window resolution (no resize yet)
• No launcher or settings UI

How to run

1. Download the zip for your platform
2. Extract into your Urban Chaos game folder (where the data folder is)
3. Run OpenChaos.exe (Windows) or OpenChaos.command (macOS)

Requirements

• Original Urban Chaos game files (Steam or GOG version)
• Windows 10+ (x64) or macOS 12+ (Apple Silicon)