John Carmack has left id Software. After helping found the company more than 20 years ago, where he helped craft experiences like Doom and Quake, Carmack has officially shifted his focus full time to virtual reality firm Oculus VR, where he'll serve as a chief technical officer. It's a position he originally took on back in August, but it seems that splitting his time between the two companies just wasn't working out. "The divided focus was challenging," he says. The move is perhaps not that surprising: Carmack has always had a fascination with building new technologies, making the Oculus Rift headset an ideal project.

"John's work on id Tech 5 and the technology for the current development work at id is complete, and his departure will not affect any current projects," id studio director Tim Willits told Polygon, referring to the game engine that will be used to power the in-development Doom 4. But while Carmack's time at id may be at an end, his influence will continue to be felt — here are some of his most important contributions.