Final Showdown Boss is the final boss in Sonic the Hedgehog Spinball (8-bit). Like many other bosses in the game, it is located in a completely separated pinball arena which the player can enter after collecting five Chaos Emeralds from Final Showdown.
The Final Showdown Boss is Dr. Robotnik in a very basic mobile with two motor engines and a powerful barrier to protect himself. For the most of the battle, he hovers around in the higher sections of the arena.
When the player enters the pinball arena where the Final Showdown Boss is located, the player has to utilize the flippers and wheel-like bumpers to launch Sonic to the higher part of the arena where Robotnik hovers around in his mobile.
At the beginning of the battle, Robotnik is surrounded by a barrier that makes it impossible for the player to hit him normally. This barrier is powered by two generators on each side of the room. To lower this barrier, the player has to turn the valves of all the generators which can be done by running on top of the valves themselves. After generators have been shut down, the valves get destroyed and Robotnik becomes vulnerable to damage.
After the barrier is lowered, Robotnik will move around the pinball arena in a heavily erratic manner, though he will normally move up and down, and sometimes left and right. To land a hit on Robotnik, Sonic has make contact with Robotnik while he is curled into a ball. After Robotnik has received eight hits, he will be defeated and the player has cleared the Final Showdown Boss. However, if the player falls down from the separated boss pinball arena, the player has to climb up back to the arena, run along four valves and repeat the same pattern.