While this Sonic spin-off is well-known for its brutally tough difficulty, that’s not the reason for its inclusion here. Nope, we’re adding Sonic Spinball because of the horrifying boss that greets you at the end of its first stage. Not only does it look absolutely terrifying, being a freakish cross between a metallic scorpion and Robotnik, it also lets out ear-piercing shrieks whenever you hit it. It’s the stuff of nightmares.