JetMizzy is a platform game where you control a jetpack-riding smiley face. On each level, the goal is to assemble an exit door from the three fragments which appear in the level in random places. The player must touch the door fragment to pick it up, then drop it above the sign which indicates the right spot. Once the entire door is assembled, it can be exited through.
The player's jetpack has a limited amount of fuel which can be replenished by standing near a gas pump. There are enemies on the levels, both moving along a preset path and popping up randomly, and contact with any of them causes the player to lose a life; once all lives are lost, the game must be started from the beginning. Some enemies can be killed with the jetpack exhaust.