We're really glad you appreciate the idea! 😁
About the feedback:
First I would have some kind of screen at the beginning with instructions, and have it say that deleting blocks gives them back.
Yup, the game deserves some kind of tutorial for the 1st run just to make sure you understand everything that is going on. 🤔
And two, when upgrading, I thought that each upgrade costed as many coins as the number above it was. The upgrade screen could be a bit more clear.
Sorry about that 😅. If we come back to this game later, we'll work on a better upgrade screen then!