Fun implementation of the 1 button constraint! It was a lot of fun to play. I really liked the art and music!
The only piece of constructive feedback I have is to investigate coyote timing. If it was included in the game the timing was too short.
The pencil drawing the line was cool. I thought it was going to give me more platforms to jump off of which would have been an interesting mechanic but was cool for the immersion too! Great job!