Thanks a lot!
We were already planning to rework the sprites and improve the levels, so that's definitely something we'll be working on.
Sadly, we just didn't have enough time before the jam ended. Our idea was to explain the controls and mechanics with holograms that appear in specifics points, while for the side effects, we wanted to show a small description when you select or hover them in the inventory.
As for the SFX, we'd really like to make them ourselves instead of using free ones, but we're still figuring out where to start.
Also, thanks for the encouragement! Seeing comments like this really motivates us to keep working on the game and to join more game jams. :)