The game is very logical, the gun changes gravity. I think if add an animation that the gun takes in the gravity energy will be great, otherwise it's non-intuitive. At first I didn't understand why that there was no feedback while my gun kept shooting something, and then it took me some time to realise that the gun had to absorb the energy before it could act on the board. If add a animation that the gravity take into the gun it will be soon understanded.
Many thanks for your play and compliment!
Indeed we also noticed this UX problem you mentioned and it is very essential for player to know the mechanics intuitively!
We are all learning from it and I believe next time we will improve this!
Many thanks for your suggestions which are very valuable to us!