I just found out about these two projects, engge and engge2, which aim at recreating the TWP engine.
I didn’t have time to have a look or try it, but the readme says that it’s able to load the ggpack files and execute the game, not bug free, but still it mostly works. Very interesting. The current version is engge2 which is in nim, a language I don’t know. The first version was in C++, which is my coding mothertongue, but it’s been discontinued.
It doesn’t read the Italian voiceover files though, not yet.