The game is pretty entertaining, and the graphics are great. Personally, I'd like to have more precise control over how objects are placed.
Other than that, I’m not sure if I was using the piston incorrectly in my playthrough, but it seemed like a worse version of the trampoline that unlocks right at the start. In fact, the catapult is so slow that it’s not even worth it if you set up the trampoline properly from the beginning. I’d definitely improve that progression for the endgame. Actually, I think the best approach for the beginning is to have no automation at all. Go from carrying them by hand to launching them with more force through upgrades, and then get the vacuum. And from there, start unlocking things like the trampoline and other automation machines.
All in all, a very good demo.