The art, music and puzzle solving all come together really nicely in your game. It is very simple, challenging and fun! I agree with @footnotesforthefuture that you could have focused more on the mechanic of platform or no platform, but it's still perfect for a game made in 3 days.
Movement and wall jumping feels great. There is not much to criticize other than the font, which I didn't like. It is minor, but you could change it if you are making another version. Good Job!