Not only are the graphics completely insane, the sound is amazing, and it is one seriously awesome action game.
Im gonna get one thing out of the way: the graphics are amazing. Many other games will look pitiful after you play this. Finally, are dreams of these next gen graphics are being realized. The lip synching is perfect, along with the character models. The surroundings though, is the most likely thing to get your attention. It even looks phenomenal on a standard tv, though you'll still want to play it on hd to get the full experience. On to the gameplay. It may have a tactical element, but there are plenty of violent elements thrown in there as well. On your gun, is a chainsaw. A chainsaw on your gun. It is the most satisfying thing in games, ever. Another particulary violent move is the curb-stomp. If you manage to "down" an enemy, you may go up to them, and proceed by stomping their head to the ground. The most common weapons you will wield are the lancer, which is a machine gun, with a chainsaw mounted on it. This is the gun you will most likely use the most. The shotgun is another very useful gun. It does just what you expect, though if you manage to get a perfect shot online, well, you will be satisfied, trust me on that. There are also standards like the longshot (sniper), the boomshot (rocket-grenade launcher type thing), and something very unique: the torquebow. I cannot begin to describe this one, you will have to experience it for yourself. The cover system is well done, while still making it easy to use. It is all done with one button: the a button. You simply tap it to get into cover, hold it down to "roadie run", and roll by tapping it as well. The a button may do to much though. Its always annoying when your roadie running and run into something, expecially in multiplayer, but dont worry, it doesnt happen much. In the single player campain, you take the role of Marcus Fenix. You will be accompanied by Dom, Cole, and Baird. There are parts of the game where you will be only with one, or with all four. They are decently smart, but dont really kill much. They will get in a chainsaw every once in awhile, but thats it. It makes up for this fault though, through coop mode. You may play it online, split screen, or system link. coop is a great way to play the game.
On to the multiplayer. A blast to play. Dont expect huge, 16 player matches. Instead, it is 4 on 4, giving it more of a teamwork element. The maps usually feel just right in size, and are very fun to play, with a variety of weapons on each one. The sound is amazing too. The soundtrack, which you may not hear over the screaming and chansaw, is pretty good if you listen to it. The voices are perfect too, be it in a cutscene, or just screaming or swearing on the battlefield. Oh, and I cant forget: the tearing of flesh from the chainsaw is great too.
The difficulty in gears can be a bit varied. You have casual mode, or "easy" mode. Then comes hardcore, quite a bit harder. Then comes the true game: insane. This is the most fun mode, but its just insane, as the name implies. Even on coop in can be very difficult in places. Though its definitly rewarding on the last cutscene. As for achievments... lets just say you wont have them all right away. You get achievements for doing every act, 5 total, on each difficulty. Also for finding all the "cog tags" little secrets in the game. Many multiplayer based ones too. For gettting 100 kills in about every weapon, for hosting 50 ranked matches, and finally, for killing 5000 kills.... will keep you busy for awhile. In short: this is a great game, and games like this do not come by often. Do yourself and buy it. Its the 360 killer app.