There is a very old game from Westwood Studios currently owned by Electronic Arts I'd like to remake, but I don't know if I can turn it into a business due to the related copyrights and possible patents on the game (I'm not even sure if you can patent a computer game or its internal mechanics).
The game was originally released in 1999, and I've heard that software patents have a lifetime of up to 20 years. Does that mean after that time I can make similar game characters/soldiers, or even make similar soundtracks to the original game content? Is it possible that the copyright on the soundtracks or the possible patents on the game can be extended further into the future even if 20 years have passed?