There is a Mickey Mouse symbol soldered onto the cartridge board of every copy of Mickey Mousecapade, right above the contacts where the cartridge plugs into the system. It's not visible without opening the cartridge.
In the North American version of the game the bosses were based on various Disney villains, with the exception of the snake and the witch bosses. The Japanese version, Mickey Mouse: Fushigi no kuni no Daibouken (Adventures in Wonderland), was based around the story and movie of Alice in Wonderland. As such, most of the game's bosses were changed to characters from the story, with the exception of Captain Hook.