In this third-person game, you play as Mickey Mouse. Mickey is dreaming in his bed and a ghost draws Mickey through his bedroom mirror, then shatters the mirror into 12 pieces. Mickey must make his way through his dream house and collect the mirror pieces so he can get back to his bedroom and wake up.
On his quest, Mickey collects stars that allow him to perform certain actions. He needs to find keys to unlock doors, figure out environmental puzzles, and the like. He may also collect "souvenirs," but these are not necessary.
This is a kids' game that can be enjoyed by adults too. It's primarily an adventure game but there are also some included arcade-style minigames, completion of which is not required to finish the game.
You can also use the Game Boy Advance Link Cable to connect to a Game Boy to play Disney's Magical Quest Starring Mickey & Minnie