Great game! Really impressive amount of content for 48hrs. Some really nice artwork too. Gaining new input as your progress is a pretty unique idea and its executed well in the level design too. Sprout is a very charming character. I played through it three times and tried your speed run challenge - my best run was 3 mins 30 seconds!
I don't have much negative to say about it except small ideas to improve/add polish e.g add a custom font and polish the UI a bit, and maybe have add atmospheric "cave-y" audio and/or less cheerful music once you are underground. A very strong entry overall!