Every so often a game comes along that changes everything. Games like Doom, Super Mario Brothers and Half-Life aren't just incredible games in their own right - they helped shape the gaming industry as a whole. Halo: Combat Evolved is one such title. As a game, Halo evolved and refined the first person shooter, making it work on a console like never before. As a product, it helped define the first generation Xbox and help Microsoft become the juggernaut of today and, as a project, it lifted its creator, Bungie, into the history books as one of the most revered developers of all time.
Games have an incredibly complicated relationship with their past. This is an industry that's fixated with the future, but too often it's one that holds its history at arm's length.
We're embarrassed by what's gone before, it seems, sometimes going as far as to compartmentalize older games under the horribly banal banner of retro gaming, a tag that's as pointless as it's revealing of the disdain we hold for anything that's over five years old.
With indie gaming re-appropriating the aesthetic of the 80s and early 90s, there has at least been a bridge built between now and then; titles like Terry Cavanagh's VVVVVV or Brian Provinciano's Retro City Rampage show that there weren't any retro games after all - they were, as they always have been, just games painted with fewer pixels.
A decade is a long time in video games, and going back to Bungie's very first Halo game goes to shows how far we've come since 2001's Combat Evolved.
While Sony strutted its stuff at Gamescom through the power of a press conference, Microsoft walked a more modest path with a Play Day event, with hands-on opportunities of a raft of Xbox 360 exclusive games including Halo: Combat Evolved Anniversary, Gears of War 3 and Forza 4.
It's a big year for Bungie. Not only does it celebrate its 20th birthday but, with the impending release of Halo: Combat Evolved Anniversary, it's also formally signing off custodianship of Master Chief to 343 Industries.