A kill screen originally wasn’t the “game over” screen, but rather a screen that appeared due to a programming error or design oversight. The most famous kill screen from classic gaming is the 256th level of Pac-Man. At this point, due to a bug, half the screen becomes garbled data, which keeps the player from collecting all the dots and clearing the board to move on. Arcade owners had to unplug or “kill” the game to start it back up again.
Level Up! The Guide to Great Video Game Design (2nd Edition) Scott Rogers
