This was fun. I like the color change mechanic and the art style. It definitely had a level of difficulty that would keep me coming back to play it because I was always pushed to finish the level.
I had some difficulty jumping if I was too close to ledges and it seemed the collision in those areas may have been just a little off. Other than that everything worked well.
The first level was very well made to introduce the concepts to the player. I was jumping around testing the controls when I heard the warning beep and say the pulsing meter. I immediately knew that I needed to do something. As the only other thing on the screen was the page it was really easy to see what I was supposed to do. It felt good.