As many folks have said, very pretty but no sound!
While the gameplay is fun, there is a lot to be desired as far as clarity goes. I couldn't easily tell what mutations I was getting outside of things like the pea-shooter or spike plants. I would've liked to see some text pop-up when I completed a mutation with maybe a little blurb on what I gained.
The game seemed to get too difficult too quickly, which it understandable. Balance is tricky during game-jams.
You're a very talented pixel-artist, and should be proud of what you've made here! Great job!