I love that you have a README (and rather in depth, and good screenshots), you'll also need a License file (main criteria for open source category).

Cute game. Love the graphics, love the sounds. It'd be cool if we can also use Space bar (jump) and WASD (moving). I like the concept (creative take on the theme) and your build is great. Nice work.

Fun! The platformer controls were a lil tricky at times, but it was lovely seeing flowers and trees blossom where you collected happy emotions. :D 

Nice game!