Commander Keen is a side-scrolling platform video game. Part of the Commander Keen series, it was released ten years after the first seven episodes in 1990–91. The game follows the titular Commander Keen, an eight-year-old child genius, as he journeys through three alien worlds to collect three plasma crystals to prevent the weapon they power, built by several enemies from previous games, from destroying the universe. The game features Keen running, jumping, and shooting through various levels while opposed by aliens, robots, and other hazards.