Wow this game really MOVES. After playing Halo so long and getting used to the deliberate 30 frames per second feel, this game will make you nauseous with its 60 frames per second. It feels very fluid, though, and is a fun game to play. The weapons are nothing spectacular for the most part (except maybe the flamethrower), and the sounds aren't too impressive. I wish this game had a little more brightness to it. Since my TV's in a bright room with a lot of sun, I found that the glare made the game hard to see. Most of the game was so dark and gloomy, or a lot of gray.
The online play requires a lot of teamwork, and is where the game really shines. The different duties of the players will be clearly defined, such as a medic helping out his injured teammates. It's a lot of well-paced action with a kick. There can be times of slowdown, but overall, its an extremely fast and fluid experience.