Thunder Force IV is the fourth installment in Technosoft's Thunder Force series, and the third and final one created for the Mega Drive. Thunder Force IV is a horizontal shoot 'em up. The story takes place two years after the events of Thunder Force III. The player takes on the role of a fighter pilot to battle the Ohn Empire, which is plotting the extinction of the human race. Like its predecessors, it is a horizontally scrolling shooter, but it also features extensive vertical scrolling with large playing fields.