Tenchu

I played this game for 3-4 years running and couldn't believe how good it was. Its brilliance is the atmosphere matched with the stealth. For example, level 4, which requires the player to simply reach a checkpoint, however in between checkpoints there are bridges, a river and numerous guards. The music stands out so much on this level with a very strong eastern tone and the night setting makes it very exciting. I also got a Japanese version which enabled you to create your own level, it is an awesome extra. What a game