Very Engaging!
The ability to shoot blindly over, or around, any structure that you are using for cover is really interesting. I think that this is done really well, and we will probably be seeing this game mechanic a lot more in the future. And speaking of using cover, if you don't do it, you will certainly pay for it by being shot to pieces. I really like how this makes you feel like you have a lot to lose. In Halo, you just run in and shoot everything before they shoot you. In Gears of War, you find cover first, or you die. So why only a 9.2 then you ask? Well, there are 2 things that seem a little disturbing (probably only to me :P ). First, though you travel with other soldiers, it seems that "you" are the only one that will die. All soldiers, including you, can regenerate from being shot, but your fellow soldiers will simple fall to the ground if they take too much damage. Then you, or one of the fellow soldiers (NPC's) can run over to them, press "X", and they are perfectly OK again. If "you" take too much damage, you die. Soldiers will not rush over and press the magic "X" button for you -- you die, and you restart from the last saved checkpoint. Secondly, I think that in a game of this quality, there should be a greater selection of weaponry. A good counter-example to Gears of War is Perfect Dark Zero. In PDZ, there are many weapons to choose from, with secondary and tertiary weapons abilities. I am not suggesting that we compare GoW to PDZ, but merely suggesting that GOW's could have improved in this area.
Worth mentioning, the difficulty of some areas are really annoying. Even in the casual setting, you will probably have to replay all the bezerker encounters several times when you first meet them.
Overall, the game does a lot more good then bad. It is really fun to play, and I fully endorse that you "buy" this one. The graphics are fantastic, and the fight mechanics are great. This game is even more fun in cooperative mode. So buy the game, get your buddy, and go save the planet.