First game I played on my Xbox and I havn't found anything better yet in the way of a first person shooter.
The game is interesting in the way as you feel you are there more because there is no hub apart from your health, you don't have anything telling you how many bullets you have or anything you just have to look at the weapons screen to find out. The hand to hand combat also makes the game alot of fun as you don't always have a gun.
Making conversation with each character is also very interesting because every character has a different personality and some will even need you to help them so that you can progress through the game.
I recommend this game to anybody who likes to play first person shooters whether you like riddick or not, the game is just outstanding and is probably better than alot of shooter games coming out today.