VGFacts

Kirby Tilt and Tumble is a GBC-exclusive game in which you use a gyrosensor to control Kirby through a bunch of levels. The cartridge is oblonged to include the gyroscope. What else is weird about this cartridge, is that it features a notch in the top right corner.



This notch is featured on Gameboy games to they can fit inside original Gameboy games.



However, GBC-exclusive games are full squares, lacking the notch, so they cannot be played in a Gameboy. The Gameboy won't even turn on.

(Note the lack of a notch)

However, Kirby Tilt and Tumble does have this notch, and can be played in an original Gameboy.





This makes Kirby Tilt and Tumble the only GBC-Exclusive game that can be run on an original Gameboy. It's also unknown as to why this cartridge has this notch, although the most logical reason is that it's re-purposed plastic from another, non-GBC exclusive game.