I beat level 3! The balloon mechanic is so fun, it would've definitely been better if you purely focused on that instead of having normal platforming levels to begin with. I also think a lot of the level design is very clunky, I got to one where the beginning spring on the wall would push you off the cliff but if you jump on it, it goes too far to reach the next platform, so I had to time it perfectly to get it right, stopped at that point.
Also definitely make your background art separate from the foreground. I like the Pizza Tower artstyle tho, if you continue this definitely go all in with the animation. Fun game.