a really cool concept, but I found out that dragging the shapes into the holes is faster and easier than using the belt. Also, the building system is a little bit confusing with so many mechanics explained at once.
I think teaching the player the mechanics slowly during the game would help a lot with that. Also, for the left-click controls , we could use shortcuts with number keys (1: building mode, 2: dragging mode, etc.) .
I really liked the music and how the game looks in general.
overall good submission!