Charming, magical, top-notch update of a classic.
The gameplay, meanwhile, has indeed been updated to 3D and brought all the way into 1997... bear with me now, I'm about to compare Castle of Illusion to Crash Bandicoot and Super Mario 64... Mickey's game probably has more in common with Crash than Mario, but it's clear his team set out to borrow elements from some of the best 3D platformers already out there. The good news is that, while there's nothing here you haven't seen somewhere else before, it's put together so extremely well you won't mind at all. There are plenty of jaw-dropping "a-ha!" moments in these levels, along with plenty of reasons to come back and replay them.
The game is mostly played on a 2D plane, with frequent brief shifts into 3D. These shifts are mostly seamless, and provide a lovely sense of depth to the whole world, especially when you realize that your horizontal progress has actually taken you into the background you saw at the beginning of the level. Like CB and SM64, there are diamonds for completionists to collect and time trials to complete for each level, and also like CB and SM64, you can explore and update the castle as you move from level to level. Exploring for secret areas and hidden items is mildly challenging, and it's actually really fun to see the castle fill up with paintings and statues as you complete your collection.
There are some frustrating elements here and there, such as when jumps don't register in time to avoid a cliff, or the narration becomes overbearing upon repetition, but these are minor issues. The game does not punish mistakes, and the narrator can be turned off when the time comes to replay sections looking for those last few diamonds and collectable items.
Castle of Illusion is a gentle-hearted game with a moderate challenge that makes up for any shortcomings with its superb and charming presentation. Yes, the game is fairly short, but the other side of that coin is that it won't wear out its welcome. For a downloadable title, and update of a game that could be finished by experts in under an hour, its length is perfect. I expect that by the time the game's charm has worn off, I will have explored and collected everything I want to explore and collect. The update team has left me wanting more, so I say to them: "get crackin' and bring on the sequel!"