After killing the Swirl in mid-flight, a black vertical line appears across the spot where the Swirl was shot. This line is referred to under the Helpful Hints section in the game's manual as the "Ghost of Yars" and warns the player to stay off its "mean streak". If the Yar is in the lower third of the screen and the black spot on its back is aligned across the vertical line at the moment the explosion vanishes, the game ends and goes into the "Game Select" screen with "HSWWSH" in place of the player's score. These are the mirrored initials of the game's creator Howard Scott Warshaw.