If you like catching butterflies, this one is for you. Excellent, solid and, nearly bug-free. Great fun with stealth.
Did I mention all the cool special and combo attacks you can do? Well there's spcial hand-to-hand combos, back stabbing combos, even some weapons have combos. Lots of variety to keep it interesting.
The level designs were OK, but the atmosphere was top-notch. This has aged very well, and runs and looks great on my tired machine.
Vin Diesel, well, whatever. Don't really care much about the character, but I haven't seen or read any of the Riddick stuff.
The story was OK, but what makes this game is the gameplay. It's what really matters.
It's a keeper.