After the first time launching the game, the launcher won't show up again and you will be unable to configure the settings.
To make the launcher open again, use -setup as an argument.
TRNG is a fan made update to the game's included level editor with a lot more features than the original one.
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:
Download and install the Tomb Raider series fullscreen border fix.
For game mods visit Core Design.