That was a really cute artstyle, and i was pleasantly surprised when i saw the Book Store pony from Canterlot!
Here's a few things you could improve on:
• If a different section of the game has the same song than the last one you were in, the song shouldn't start over. I mean the alley where the comic book store is, and the store itself use the same music.
• Spike's fire breathing ability should be able to do it from whatever side he is looking at. The left side is the one he always breathes fire at. Same for gobbling, though you can only do that to the gem on the left.
• As Marcsello pointed out, i had the same opinion about the spawnpoints ^^
I would love if you made something better with the MLP license, and longer!