Romero's Night of the Living Dead
Game: Doom II
Remember that cryptic voice in the last stage? That was a backward-masked John Romero saying, "To win the game, you must kill me—John Romero."
Although you really just had to shoot rockets into a hole to beat the game, you could use the idclip cheat and walk through the wall to see what was in the hole: Romero's head on a stick. Sucks to your asthmar, Romero!