I played the in development build. It works well, I got up to 17x17. I didn't really get the overcharge mechanic whilst playing, it kinda seemed like I'd always lose charge since I was usually above 9 and then it'd stop working sometimes. Maybe a some UI segment or effects at full charge would help. The losing charge feels off as it's like the game wants me to rush in a puzzle game.
Looking forward to seeing what you do with it.