This was a cute little puzzler.
I didn't realise on my first playthrough that I could stand on seeds. After I discovered that, I went back to play for a third time, and that added some nice extra dimension to a couple of puzzles that felt like they otherwise would have been shallow.
The only bug I found was that if you are standing on a seed and shoot enough that the seed is removed from beneath you, you will hang in mid air until you walk or shoot again.
I found myself wishing that there were some sound effects, but the music provides nice ambience and offsets their absence.
If you were continuing development on this, it might be worth keeping a variable or two around to keep track of the player's position and velocity so that level transitions can be more seamless.
Your Linux build does not have executable permissions. You should update instructions on your game page to indicate that players should do this (they can enable this in the properties dialogue of their favourite file browser application or use the chmod command). If you're on Windows and would like to set this yourself, I made a free tool for managing that.
I really enjoyed playing this through! Good work :)