Making your own engine to make this game is an truly impressive feat so already that is worthy of praise. You have a great starting point for a deeper game here where your block placement and what you place on top of could create a lot of additional strategy. I would also suggest for readability it might be easier for the player to see the height of the towers if all blocks where the same colour on the same floor. Then at a glance you could see how tall your structure is. Great work getting this done!
