Overclocker
Very rare3.8%ObjectiveOptionalSingle-player
Single Player
Complete Test Chamber 10 in 70 seconds
Chapter 3, Test Chamber 10 - solve the whole thing within 70 seconds of entering. Play it once normally to learn the route, then reload the chamber (chapter select or a save) and run it clean. 70 seconds is generous once you know the solution, so a practice run or two is all it takes.