Platform: Xbox, PC 
Release date: November 9, 2004

Halo 2 revolutionized online first-person shooters. Period.

Sure, plenty of online shooters existed prior to Halo 2's arrival, but they were firmly entrenched in the world of the PC master race. A console online multiplayer FPS was such a game changer, younger gamers can hardly fathom a world where they didn't exist. 

Halo 2 took everything, and we mean everything, from the first title and improved upon it. Ambition is the only real fault of the title. Dual wielding, an expansion of the narrative and lore that seemed digestible, and online mutliplayer were all awaiting gamers when they got their hands on this Xbox exclusive.

We all signed up in droves for Xbox Live, making it the premire online subsrciption service for years to come. Online voice chat, parties, and massive online battles were all a first to console owners and it's thanks to Halo 2.