You are Riddick and you're locked in Butcher Bay Maximum Security Prison. You have to find the means to get out and off the planet. You have to use mainly your stealth, though there are weapons to be enjoyed throughout. You have to pay attention to guards and their moves. There are some heavy guardians that are a pain in the ass. The game is not easy as one might have thought.
DARKNESS is your friend as Riddick states. You use properly and you'll succeed in your plans to escape. You have hand to hand combat and that is great.
This was my second walkthrough of the game and I must say it's still impressive.