Rocket Man is a platformer where the player has to collect diamonds. The diamonds are located on the far left side of the screen and the player starts out to the right. The right side consists of platforms and ladders but to get to the diamonds the player will need a jetpack to fly across the gap that separates them from the rest of the screen. To use the jetpack the player first has to collect fuel cans which appear in random positions. Once the gauge indicates there is enough fuel in the tank the player can pick up the jetpack and go get the diamonds. When the fuel runs out the player has to go back and collect more fuel. Beneath the platforms are water that the player has to avoid. There is also a bubble that moves around the screen trying to catch the player. When it succeeds it drags the player down into the water. Contact with water leads to a lost life.

The game consist of six levels each with a different platform layout. On the first three levels the bubble gets increasingly better at homing in on the player, making the game harder. On levels 4 to 6 the jetpack is replaced by a vulture and instead of collecting fuel the player has to collect lamb legs to feed the vultur