Re:GTA III and Vice City fully reverse engineered: re3
by softwhale on Sunday February 14, 2021 @10:42AM
(#26133259)
Apparently, this project requires the game assets to work - so you have to own a (legitimate) PC version of the game. https://github.com/GTAmodding/re3#intro
Of course, R*/Take-Two could always make a case.