Atomic Robo-Kid(1988)

Atomic Robo-Kid is a horizontally scrolling shooter released in arcades by UPL. The player controls the titular character through six stages of increasing difficulty, facing an alien "governor" boss (which are so large as to be considered levels in and of themselves, as some of the bosses take up several screens) at the end of each level, followed by a "duel" level against other Robo-Kid sized robots. Many levels branch into others, giving the player the choice over which zone to enter next, increasing replayability.