I played through this game in co-op and single player. It has excellent graphics, better than almost any game I've played. I agree the sound is a little skewed at times based on your position relative to certain terrain and opponents, but not so much so that I was confused or anything, just sort of "Oh, there he is", when the sound wasn't coming from exactly the right spot, but it's close enough. Gears of War isn't perfect in this regard either like for example on maps with two levels, someone upstairs sounds as if they're right next to you. They don't have the height thing figured out yet obviously.
The AI on beginner and normal levels don't offer the type of AI resistance you find in say the Call of Duty series on a relative difficulty setting. The final two levels ramp it up in China and Miami on professional. These two will have you working some to stay alive, but the rest of the game is relatively easy if you're an experienced shooter.
The ending is very anti-climatic as I agree with Tom in that it pretty much "blows". Without spoiling it, let's just say they seem to be saving something for a sequel.
Also this huge element in the game called "Aggro", doesn't always work correctly if you're playing in single player mode. This can be extremely annoying when you are attacking what is called a "heavy" that is supposed to be killed only while being flanked ( I learned to just RPG them). Since your AI guy needs to use his gun for "Aggro" to be initiated, and for whatever reason he sometimes simply will not shoot at the enemy when put in the aggressive hold mode and in a position to hit them.
Gamestop pre-order copies had a one-time use code that unlocks two-weapons, a sniper rifle and a SMG. Since these are one-time use and I didn't buy through Gamestop. I've still yet to get these weapons, which sucks in my opinion, as I've already completed the game and don't have everything there is to offer.
The multiplayer matches are a bit spotty, but I never come to expect much from it unless that seems to be a point of emphasis in hype leading up to release. This games' primary objective was to be co-op campaign driven, which it does pretty nicely.
