Love the low-fi presentation for this. The gameplay reminds me a kernel of one of my favorite one-input games "One More Line". There are two things that I think OML did that would be worth considering. First, centripetal force: I want to rocket off that disc out of control rather than a perfect air-control jump. Gives you a bit more depth rather just being about perfect timing. The second is strategy. OML pulls the camera out far enough so that you've always got a chance to see where your next move is. Here, sometimes I felt tricked by noticing something offscreen that was upcoming.
It's tough to make a single-input game that's really engaging, but I think you've got a great start!