Robotnik's Ship is the fourth and final boss of Sonic Spinball for the Sega Mega Drive, awaiting Sonic at the end of Showdown. This is a difficult one. As with all of Spinball's bosses, Robotnik has no means of harming Sonic directly; but he does have plenty of ways to throw the heroic hedgehog out of the boss area, sending him air surfing down towards the foot of the stage so he has to work his way back up to the top.
For victory here, Sonic must flip onto the button directly underneath Robotnik's shielded control room, sequentially deactivating the various passive defences that guard the glass shield over the Doctor's pod: first the grabbing claws, and then the windsocks which otherwise throw Sonic into (and possibly out of) the plexiglass windows at the side of the boss room. Eventually, Sonic is able to crack a hit against Ivo's personal bubble as many times as he can. If Sonic either hits the button again or takes too long, the defenses will come back.
While normally we have just Sonic plummeting to probable doom all the way from space, this end sequence shows Robotnik falling with him. Sonic is rescued in time-honoured fashion by Tails on the Tornado; meanwhile, Robotnik is left to tumble back into the crumbling maw of the Veg-O-Fortress, as Mt. Mobius collapses into the sea.
||The despicable Dr. Robotnik scrambles frantically to blast off. He's desperate, and will even try to fight Sonic off with slashing mechanical claws. Timing is everything!
— Sonic Spinball US manual