Francesco Poli wrote:
If they are striving for near exact (or even very, very similar) re-creation then I'm nearly certain they are infringing the copyright via "mise-en-scene". The debate over openTTD is whether or not recreating a game engine is a violation of copyright. The game engine consists of the interface, and the game rules, both of which are thought by (at least) some, to be un-copyrightable.http://freedoom.sourceforge.net/), but (maybe) they are infringing on the original Doom game data copyright... :-/