How to play
go left: press the left half of the screen (for touch screen device), or press the key (for keyboard or joystick)
go right: press the right half of the screen, or press the key
start/resume game: press the play again / continue button on screen, or press the Space / Ok key
life: hitting spikes on the top or on a floor reduces the player's life, landing on a floor (without spikes) increases the player's life
game over: falling off the bottom or running out of life