First off, contgrats at making a very complete game! I had a good time playing through the whole thing, most everything fits together quite nicely. A couple things I can critique:
* I'd have loved to play with my controller's D-pad instead of joystick
* Some pipes didn't work for me with controller (had to use the keyboard to go into left and down pipes
* You can think you found a secret at the end of pipe pond and walk all the way to the beginning of the level on accident (with no way back!)
* Try to avoid "mixels", or art with different sized pixels. Some of the art was a little distracting to me as I could tell the pixel scales were completely different with certain assets (like the spike balls)
Otherwise, this is a great entry that you should be proud of!