What genre is the 1993 spin-off Sonic Spinball?

The 1993 Sonic Spinball is a pinball game.

Sega Technical Institute developed Sonic Spinball for the Sega Genesis, with Sega publishing it in November 1993. Instead of running through conventional platforming stages, Sonic functions as the ball inside enormous pinball-machine-like environments. Players use flippers, bumpers, switches, loops, and targets to guide him through four levels.

The game grew from Sega of America's desire for a Sonic release during the 1993 holiday season, while the Japanese Sonic Team staff were busy with Sonic the Hedgehog 3 and Sonic & Knuckles. Designer Peter Morawiec drew inspiration from the popularity of Casino Night Zone in Sonic the Hedgehog 2 and from the Amiga game Pinball Dreams.

A common mix-up is calling Spinball a platform game simply because it stars Sonic. It includes platforming-style objectives and directional control, but its defining genre is pinball. The goal is to collect Chaos Emeralds, defeat each level's boss, and free animals from Doctor Robotnik's fortress.