nice short little platformer! I thought you had some nice visual effects (like the lighting in the darker levels & trailing player effect) and though the jump was pretty floaty, it really seemed to work for the game, especially with the double jump later on!

It took a minute for me to understand the upgrades and sometimes I didn't even really notice a difference. I would suggest some sort of visual representation on the screen to tell the player "speed increased" or "higher jump unlocked", whatever the upgrade may be. Also the music was a little repetitive and there's one note that repeats throughout that's just way louder than the rest of the track. 

Overall, good job!