Love the theme music! Really charming graphics and sounds. I wasn't sure I'd like the multi-tasking at first, but it turned out to be really fun after I gave it a try. Adding more mechanics as you progress was a nice touch. I think there could have been a little more feedback to the player with the energy bar, especially with the 60% button mechanic. The energy bar sliding up and down made it not immediately apparent if I was having an effect on it or not, so it felt a little bit delayed.
I played for a good while, and I think I was getting close to the end on one of the final checkpoints, but it got a little too overwhelming and I gave up before I beat it. But I appreciate how many levels you designed to make this feel like a full length experience!
Really nice execution on the theme, and love the cohesive aesthetic of the art & sound design. Great job!