It is a puzzle/adventure. They give you a gun with sonic rounds and you have to use the environment to eliminate the enemy. You can't just shoot the enemy (well, you can but it only stuns them), you have to figure out how to kill them using other means. The majority of the time, you're not shooting, but puzzle/platforming your way around.The Amazing Tea Alligator said:
Honestly, I got it and I love it. The dorky support character with the horrible accent is annoying, and there are some frustrating bits, but so far I'm having a ball with it.
I really like the fact that it uses environmental things like Bioshock did, but, unlike Bioshock where it was easier to just shoot enemies, you actually have to use them in order to progress.
Don't believe the negative reviews, it's a great game for the money.