It's nice cute and fast platformer.
I kept thinking it would be more intuitive if jump in the air was double jump which used up one of your stars. As is it now you can kind of cheese some obstacles by spamming up shoot. Like neutral jump in the air would be the current up+action, and side + jump in the air would be the current action in the air.
Also if the stars came back with landing or hitting a powerup, it would be more satisfying and puzzle like instead of you can kind of grind out a big gap with jump spam.
It would be nice to see the cutoff time for the stars in the results screen even if you exceed it.