Speed Run Achievement in Doom 3: BFG Edition
Complete the DOOM 3 single player campaign in 10 hours or less
How to unlock Speed Run
Finally! An amazing FPS game with a speed-run achievement! You’ll be surprised how easy this actually is, since the best speed-run in the world was done in less than two hours, which gives you eight whole hours of leeway.
Below is a speed-run video from the Speed Demons Archive on Nightmare which should help you in getting a good time.