The concept is great, a one button game with a very unique mechanic, I haven't seen anything like it!
The thing I would tweak a bit is the jumper with the clouds, they seem to push you higher or lower depending on how long you press the key, I think it adds an unnecessary challenge as this part seems to be more about timing than precision jumping. It would also be nice to have a restart at checkpoint key/button to shorten the wait to restart a challenge.