The best game on the 360, and my favorite game of all time.
The graphics were amazing and crisp from step one, even of a Standard-Definition television. The sound was unbelievable coming from my TV's stereo speakers, and even more so from my Surround Sound. A conflict I usually have with sound in shooters is hearing your teammates (or sometimes enemies) through all the shooting and explosions going on around you, but that was not so in Gears of War. Everything was audible, assuring that I did not miss any important information.
The gameplay too was more than I expected it to be. I expected to be a little shaky at the game's mechanics, as I am used to first person shooters. However, yet again, Gears of War surprised me with a fast-reacting and natural gameplay design.
As for the singleplayer: The enemies come at you fast, and you have to plan your attack. At least to a higher degree than most shooter games. This is not just a run-and-gun mindless action game. Often, you will find yourself in a scenario where you can't just run up and shoot the enemy, but where you must flank them by running through buildings or alleyways, and sneaking up on them. Always taking cover to ensure you don't get flanked, yourself. Your teammates are smart and provide accurate covering fire, however sometimes they will be knocked to the ground, unable to move. The game has a GRAW-like healing technique. You must run up to your fallen teammate, and heal him with the X button. Also, while playing singleplayer, you can invite one of your friends to play co-op with you over Xbox Live, and can start from where you left off. Your friend will assume the role of Dominic, and fight beside you in place of the NPC Dom. In co-op over Xbox Live or System Link, if you die, Dom can revive you and vice-versa. In split-screen this is not so.
As for the Multiplayer: You will fight in environments that seem to pop right out of singleplayer, by which I mean you can tell about where in the storyline you might run into a place like this. There are 3 team-based gamemodes. There are no respawns in Gears of War. In Warzone, you will choose between the Human team, or the Locust team, and fight to the death. In ranked matches, whoever wins 5 rounds first, wins the game. In Assassination, each team has a team leader, and the opposing team must take that leader out. Larger guns can only be picked up by team leaders, but once the team leader drops them, they are fair game for any of his teammates. And finally, Execution, which is similar to Warzone, but once an enemy is down, they can tap A repeatedly to revive themselves. However, the opposing team can finish you off by performing a special close-range attack called an execution.
In the end, this is a great game for 360 owners and I recommend it to everyone. Even without Xbox Live, HDTV, or Surround Sound, this game can provide top-notch quality in not only graphics and sound, but replayability and gameplay.