According to Warren Spector, there were plans for a third Epic Mickey game. The game would have been a full blown musical with a much greater emphasis on multiplayer than Epic Mickey 2. The game was canceled after the lackluster performance of Power of Two, as well as Disney's management changing focus to the mobile gaming market.
Contributed by CLXcool
In an interview, Warren Spector stated that 'You can literally get through the game without ever using paint. Or, without ever using thinner'. QA tester Irvin Chavira also mentioned that you can complete the core game without using either.

However, in the final game, it is a necessity at certain parts to use both paint and thinner to move forward.
Contributed by RadSpyro
In the first game, Gremlin Sparks is a yellow faced Gremlin with a red nose and purple outfit. In the sequel, his skin is entirely blue and his outfit has changed to yellow and red.
Contributed by RadSpyro
If the player paints the Animatronic Dragon but thins Prescott's Mech, the ending will still show Prescott's Mech in perfect condition just behind the Dragon. Shortly after, Prescott's Mech will be shown ruined.
Contributed by RadSpyro
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Before the game had been officially announced, an online survey was conducted. People were asked to choose from a selection of possible box arts and a selection of possible names. While the final title was among the possible choices, the box art used for the final product was not.
Contributed by RadSpyro
The Dahl Engineering Corridors (D.E.C.) are named after Roald Dahl, the creator of the Gremlins.
Contributed by RadSpyro
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A development screenshot suggests that the Seven Dwarfs were originally going to be in the game.
Contributed by RadSpyro
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In the first game, Gremlin Prescott's coat was blue. In the sequel, it appears purple at first but suddenly becomes blue again towards the end of the game.
Contributed by RadSpyro
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The Challenge image for 'Full-court Prescott' appears to be based on an older model, as he is wearing two plain white gloves, instead of the unique gloves he usually wears through-out the game.
Contributed by RadSpyro
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Even before Oswald obtains his remote, he will make motions as though he has it in his hand.
Contributed by RadSpyro