Lemmings Paintball Decompilation

This project is a matching decompilation of Lemmings Paintball, an action game in the Lemmings franchise developed by Visual Sciences and published by Psygnosis in 1996 for Windows 95.

The goal is to reconstruct the game's codebase in idiomatic, maintainable C++ while preserving its original behavior and matching the original machine code as closely as possible. The resulting codebase will serve as a faithful reference and foundation for future ports.

[!NOTE] This project targets 32-bit Windows using Microsoft Visual C++ 4.0. </br> For a modern, cross-platform version, see lemball-portable.

Reconstruction

The Macintosh 68000 version retained Metrowerks and MacsBug debugging symbols, providing over 2,800 original function names and revealing C++ class hierarchies.

The original Windows executable lacks debugging symbols, so functions were matched across versions using strings, constants, algorithms, virtual tables, object layouts, and call relationships.

Matching

Functions are compared against the original executable using reccmp.

• Exact: Non-stub functions with 100% raw assembly similarity.
• Fuzzy: Raw assembly similarity, including equivalent functions.
• Effective: Non-stub exact matches and reccmp equivalence results.

Exact and fuzzy metrics are tracked on decomp.dev and bytematch.dev.

Building

Requires Python 3.10+, Git, and PowerShell.

Install dependencies and the MSVC 4.0 toolchain:

python -m venv .decomp-venv
.\.decomp-venv\Scripts\Activate.ps1
python -m pip install -r requirements.txt
git clone https://github.com/vonhoff/MSVC400 msvc400

Build the executable:

.\.decomp-venv\Scripts\Activate.ps1
python tools/make_binary.py

Use --disable-startup-checks to bypass CD-ROM and installation checks.

References

• The Cutting Room Floor
• Game Data Digs
• Reverse Engineering a DOS Game with Ghidra and Codex
• isledecomp/isle
• marijnvdwerf/legoland

AI Disclosure

AI is used for research, tooling, and code reconstruction. All code is manually reviewed.

Legal

This is an unofficial project unaffiliated with the original rights holders. Original game assets are not included.

No license is granted for reconstructed game code. Independent code is released under the Unlicense.