Riddick is what you would expect from a Splinter Cell combined with a Halo, pure awesomeness.
In all seriousness, Riddick is a good first person shooter, combined with a pretty original melee and hand-to-hand combat system, making you not so harmless when armless. This game also requires a good amount of stealth, so going guns blazing will get you killed. Instead, hide in the shadows and use your unique EyeShine ability to see in the darkness, wait for your enemy to turn his back, then strike.
The story is pretty decent. You are trying to escape a prison...hmm, to be honest, I didn't watch any of the movies, so I don't know anything else. The game does center around you beating the guards and other inmates.
The graphics are great. The facial expressions of Riddick and other NPCs are about second to none, The setting is, of course, a dingy dark prison, and that is shown well by the game's graphics.
There is no multiplayer or co-op, so the only replay value is in collecting the cigarettes packs throughout the games thirty-odd levels, the considerably high difficulty of the game, and the back-tracking you must often do are the drawbacks, hopefully some what lessened in The Chronicles of Riddick: Assault On Dark Athena.
If you are reading this and are considering buying the game, wait for the release, The Chronicles of Riddick: Assault On Dark Athena. However, if you are strapped for cash or just lack a next-gen console, you can find it for about fifteen bucks.
An 8.5 of 10.0 for being a great, gritty game