Hey I have some suggestions:
- Music could keep playing between restarts
- Full screen messes up the popups
- You should be able to bring back the instructions if you closed them
- If you place multiple blocks would be nice if it kept the block selected when placing them so you don't have to click it every time
- Would be nice if you could move the camera as well as zoom. Maybe I missed it
I love the sandbox. There is potential here for a great puzzle game.