Donkey Kong 3 is a vertical fixed-screen shooter. You play as Stanley the Bugman, a greenhouse keeper armed with a can of bug spray. Donkey Kong has invaded the greenhouse and is hanging from the rafters, shaking loose swarms of bees, beetles, butterflies, and other insects that descend toward the bottom of the screen.
Your goal is to spray Donkey Kong from below, pushing him steadily upward into a beehive at the top of the screen to clear the stage. While doing this, you must also fend off the falling insects and protect three flowers at the bottom — if all three are stolen, the game ends regardless of remaining lives.
Stanley moves across three vertical platforms connected by short ladders, giving him left, center, and right firing positions. A limited-use Super Spray power-up doubles his firepower and pushes Donkey Kong upward much faster. Three stage types rotate — a greenhouse, a jungle, and a beehive — each with different enemy patterns and escalating difficulty.