Just a small suggestion that I could see some use for, Different types of balls and a menu to choose which one you will be able to choose in the game, There could also be a challenge mode to unlock balls to play with in the destructive sandbox part

The challenge mode, you have to destroy some specific blocks (indicated with a distinct border color) and using balls lose points, It would be similar to a small game called blosics 2. http://www.physicsgames.net/game/Blosics_2_Level_Pack.html

Just an Idea for what could be next,

With update 0.7.0 I have figured out an inventory system that will work for just about anything. I am going to add more projectiles in the future but since implementing the different blocks took way too long, I don't know when I'll start working on it again.

I'm just not feeling like making any updates for a couple of weeks. I also have to figure out the future of this project, been working on it for 2+ years.