On stage one, the gorilla rolls barrels down the screen. These can be avoided, jumped over, or smashed with a hammer that can be collected and carried for a short time. If a barrel reaches the flaming barrel at the bottom of the screen, it will sometimes become a fireball that rolls erratically along girders and up and down ladders.
On stage two, conveyor belts that occasionally change direction carry trays of cement that are fatal to the touch. Fireballs appear from a central furnace. Ladders to the top level extend and retract. There is again a hammer that can be used to smash the fireballs and the cement trays.
On stage three, the gorilla throws bouncing I-beams that must be avoided. Constantly moving elevators must be jumped on to progress.
On stage four, eight rivets hold the top of the building together. Running or jumping over each rivet makes it disappear. When all eight rivets have been removed, the stage is complete, and the game loops back to stage one, speeding up and adding barrels and cement trays.