In a nutshell:
One of the most highly rated games of E3, Gears of War is looking likely to be the Xbox 360’s Christmas blockbuster with the best graphics yet seen on the system and a tactical twist on the usual shoot ‘em-up gameplay.
With Halo still at least a year out this is currently the Xbox 360’s premier exclusive shoot ‘em-up. Using a third person, over the shoulder, view rather than the usual first person viewpoint the game emphasis the importance of cover and tactics rather than just running and gunning. The question of cover becomes particularly important given the impressively destructible environments you fight in, which create a constantly shifting battlefield for you to navigate. As you’d expect the game also contains an extensive suite of multiplayer and co-op modes for play over Xbox Live.
Most exciting moment:
The graphics are stunning, nearly photorealistic, but the greatest guilty pleasure in the game so far is the "chainsaw bayonet" and the OTT spurt of gore it extracts from bad guys.
Since you ask:
Gears of War developers Epic Games are also responsible for the Unreal Engine 3 graphics engine which is used in many other games from Assassin’s Creed to Lost Odyssey.
The bottom line:
Who needs Halo when the Gears of War are turning as smartly as this?