I do not how they made it, but this game is even better than Vice City! Incredible landscapes, it makes me wish to jump on a (stolen) motorbike and travel through California and Nevada. Well... almost.
Good story, excellent musics, sounds, high longevity (completing it at 100% is nearly impossible without cheating). The only thing missing is multiplayer, but the fans made it possible with a free mods, this is the way to go!