OpenTomb is a cross-platform reimplementation of classic Tomb Raider 5 engines
that were developed by now defunct Core Design. It is not a patcher or DLL
extension of already existing engines.

The project does not use any old Tomb Raider source code, because all attempts
to retrieve sources from Eidos / Core were in vain, despite many petitions by
the community. Instead, everything is being developed completely from scratch.