Thanks! I did some in-person playtesting with some other puzzle game friends and agree that there's a lot that could be made more intuitive. A ghost piece would definitely help show the first-order effects, and the art could be _significantly_ clarified to show what the properties on each piece are in order to hopefully make understanding the second-order effects easier.
The horizontal piece thing is something I was toying around with. The idea is that hard dropping a piece does its smashing effect along the axis of the piece, so if you wanted to smash things horizontally, you'd drop the piece horizontally. In practice, I'm not sure how useful that actually wound up being, so it's definitely going to be revisited if I wind up doing another pass on it.


