This is a nice little game! The directions in the description were a bit opaque, but I eventually worked out what the game is doing and how to do well.
One bug I found was that it's possible to select the same number twice for a single operation, resulting in the operation execution clearing one operator symbol and one number total. If you do this at all, you end up with a grid with no operator symbols, just numbers, and no apparent way to proceed as the power level drops...
I really liked the buildings lighting up in the background as grids are cleared. I wish I could do well enough to see it fully lit!