You Only Live Once is a side-scrolling platform game with a twist: The player only receives one life. In the game the player has to save the protagonist's girlfriend. She's been kidnapped by an evil giant pink lizard. Unfortunately the player character is no super hero and only has one life with which to accomplish the task.
The game plays like a standard scrolling platform game and borrows heavily from Super Mario Bros.. The protagonist can move left and right and jump on enemies to kill them. He has to avoid getting hit by enemies, spikes and avoid falling in pits. When the player character dies all there is left to do is watch how the story advances as the tragedy of his death unfolds. There are no do-overs.