Thanks for trying it out!
The stacking was originally planned to be a sort of defence mechanic but in the end it worked as a way to gather the gems to throw them all at once, currently on throw you can only chuck one at a time but if you stack them you grab the entire group :))
The first thing our friend did when I handed him the game was run in the opposite direction and fall infinitely haha, I'm sure we will fix that up sometime!