Doing better than what I've done ;-;

Simple and satisfying! The jumping and collecting sounds are very pleasing, but I found myself wanting more variety in the level layout. As a suggestion, maybe you could add a few obstacles and vary the platform height? Still, it's a solid starting point with plenty of room if you want to expand! :) 

Some more platforms and obstacles would've been welcome, as it stands the game provides no challenge. The exit button doesn't work, seemingly.

A very simple idea nicely executed. The controls work well. I would like to have seen the game do more with the idea, like introduce more mechanics or challenges or different level designs.