Download it here
A "flexible patcher" which unlocks many game hidden features
Tomb Raider Mouse Helper is a utility which allows controlling Lara with the mouse. It also maps the WASD keys to enable a more modern, keyboard+mouse control scheme.
OpenTomb is an open source remake of the Tomb Raider engine. It overhauls almost all aspects of the game engine, along with adding cross-platform support for modern operating systems and Lua scripting support.
Important links regarding the project:
Use Helix Mod: Tomb Raider 2-3-4-5 to disable.
Download and install the Tomb Raider series fullscreen border fix.
For game mods visit Core Design.