One of the best games I've ever played
You get to play as Riddick, who is portrayed by Vin Diesel - just like in the movie. They even used his voice for the game.
It's a cool game, it looks and feels very realistic. It has atmosphere, something which not many games have. You get caught in really fast, there isn't a single moment in which you can say you're bored.
You have stealth (felt like I was playing Splinter Cell or Aliens vs Predator - with the alien), first person hand to hand combat and with weapons - kind of like in Condemned, and then you have your basic shooter. You also have interaction with characters, quests - bit like Deus Ex but the story is more linear.
The story is captivating, dialogs and characters are well thought, graphics and sounds are top of the line.
Bottom line, this is probably one of the best movie inspired games ever made, and an instant classic which you will no doubt enjoy from the start to the end.
An amazing game.