Probably the best first person shooter of the year... as sick as it is. If you loved playin BLACK on ps2/xbox then there's no doubt you'll love this. Much like BLACK you'll see yourself reload ur gun and give the environment some real damage :P. For fans of Gears (= me!) ya got ur head poppin', body blowin' chaos which we all love.
The only campaign mode that will get you achievements is if you play it on hard; all other achievments are for acquiring on xbox live but nonetheless it is a thoroughly enjoyable game to play on xbox live. When you get shot a certain amount of times you go down (much like in gears, only on ur side) and you get a second chance to get'em back with ur pistol which is a really cool thing to add to the gameplay (only on xbox live). The enemy does indeed react to ur shots, example...S, you shoot a guy in the neck they hold there neck in agony. You shoot a guys leg off, they crawl along the ground (boy is that a freaky 1 lol). Controls are relatively simplistic and easy to get use to.
Now down to the technical side of things:
Weapons - you can carry 3 weapons at a time (2 pistols counting as 1), you have various types of Assault Rifles, Shotguns, Pistols, Submachine guns, Light Machine Guns, Sniper Rifles and Explosives. Special Weapons - Mounted Guns and C4 charges. Grenades - Frag (Sing Pl.) Multiplayer only - Smoke, Phosphorous and Flashbang.
Xbox Live modes - Deathmatch, Team Deathmatch, Capture the Flag, Elimination, Team Elimination and demolition.
Pros: Intense, straight forward warfare including freakishly realistic AI and lush environments. Plenty of enemies.
Cons: hardly compares to other tactical fps i.e. Bioshock, COD4 and Halo 3