A classic in gaming!
Even though is a single player only game, the lenght is fairly high for a game in the genre. The replayability, however, is not good, lacking a New Game plus option (at least that I'm aware of) and after a great twist the urge to play it again will be short, I'm afraid.
The game can drag a little by its end but its well worth the journey.
One classic in gaming, no doubt about it.