Interesting
Interesting concept for a game. Have you read Rudy Rucker's "The Fourth Dimension"? I'm guessing that's the inspiration here, so for others who find the game interesting, it's recommended reading.
The fun factor is a bit limited... maybe if you incorporated other challenges. For instance, you show the cross-sections of a more complex image and have to pick it out of a lineup of 4. In harder levels, you could have them rotated.
I notice that you do have other game modes, but they're all locked, with no indication of how to unlock them, so I don't know if you have anything like that.