Left 4 Dead and Portal 2 are the latest big 360 games to join the Xbox One's roster of backwards compatible titles.
Valve's outstanding multiplayer shooter and incredible narrative-driven puzzler are available on Xbox One today. They join their siblings Left 4 Dead 2 and Portal: Still Alive. This is great news for fans of Valve, and bodes well for the possibility of The Orange Box (Half-Life 2, Half-Life 2: Episode One, Half-Life 2: Episode Two, Portal, and Team Fortress 2) becoming backwards compatible at a future date.
As always, we'll let you know as more Xbox 360 games are added to Xbox One!
Source(s): Larry Hyrb/Major Nelson's Twitter Account