First things first: Gears of War is, without any doubt, a sofware masterpiece.
Graphics - Image and graphics are amazing, although the option for the overall grey environment may not please everyone. Still, you won't find any flaws in your screen, unless you are specifically looking for them, and even then, won't be easy. The whole atmosphere created, the style of the armours and weapons, the areas built where you will be fighting for your life, and your enemies( the locust) all seem to blend in, part of the same world, to make an explosive visual cocktail. The cut-scenes are not many, but they are competent and deliver, achieving the purpose of drawing you in to the story and the characters.
Controls - Simple and effective, easy to learn, and to use, just like you want in a frantic shooter.
Duration - Gears of war has itself a pretty long campaign. The time you will take to finish it, will depend mainly on the difficulty you choose, but even on the easiest modes, you will find around 10 hours of entertainment. And that's without counting with the multiplayer, that will take those 10 hours and multiply it tenfold.
Gameplay - With an effective cover system, the first of its kind to work out perfectly with efficiency, after a few attempts to introduce similar systems on other titles, the developers made the best of it, using the cover to deliver some great action moments. with a single press of a button, Marcus( you) will hide behind a wall, a tree, a car, whatever cover he may find closer, crouching when necessary to keep himself out of harm's way. And from cover, he can shot out, either leaning, or simply shooting blind. These features may seem small, but the fact is that they change the gameplay making it a lot more realistic and down right bloody. With a good range of diferent enemies to fight, diferent scenarios, great weapons that are fun to use, developers honor their name: it's just Epic.
Multiplayer - With lots of maps, and all the usual modes, lots of gamers making a large community, it's fun all the way. Not easy to get in, since there are many "pros" already used to it.
In the end, Gears of War is a brilliant game, that will endure in the memory of all those who play it, like something memorable should.