The longer you hold down the fire button, the farther your character can throw rocks. The boy must avoid monsters while attempting to make it to the top of each level and proceed on to the next. There are a number of flags at the top of each level that must be destroyed in order to proceed to next level.
Occasionally, there is a bonus round where your character flys back and forth at the top of the screen in a hot-air balloon in an attempt to drop rocks down upon a monster that is running at the bottom of the screen. There is a fuel gauge that determines when the bonus round will end.