Maybe spawn some rings after 200m, that pierce and bombs are "useless" against, and the next upgrade can work on them better. Like 0 blocks between 200 and 205 just a 5m ring.
I like. Well done. Little grindy first ~30min, had to go Idle sometimes. Make demo on steam! (prob need two extra upgrade categories, IDK) after 300m not much to do
Small feedback: interface is a little clunky, clicks don't register, numbers are hard to read, font not properly aligned in buttons. And cannonballs spawn too far away from the cannons.
