GameObserver writes: "Why is Halo great? Answers are varied, and objective. But ask many why they keep flooding back for more, and they'll answer with one, simple word: multiplayer. Arguably Bungie's most influential innovation, Halo's multiplayer paved the way for console shooters that followed it. Halo: Combat Evolved made system linked Xboxs fashionable. Halo 2's groundbreaking online matchmaking carried Xbox LIVE's fledgling years on the crest of a wave, breaking only when Halo 3 refined the process further on the Xbox 360. Without Halo, would we have enjoyed the brutal online thrills of Modern Warfare or Killzone 2? Now, in the post CoD/Gears of War world, it's time for Halo to return."