To celebrate Wolfenstein 3D's 20th anniversary, here's a video of programmer John Carmack playing and talking his way through the 1992 first-person shooter.

Carmack, the co-founder of Id Software and one of the key programmers behind the Quake and Doom series, has a lot of interesting things to say about the old Nazi-packed shooter (which you can now play for free on your browser).

Wolfenstein 3D Director's Commentary with John Carmack [YouTube]