This one had me hooked! Definitely required a lot of focus but the gameplay loop was really satisfying. I really enjoyed the visual style, although the filter-like effect did make it a bit difficult to read text at times. The charging and discharging idea is a really interesting one to bring into a tower defense game, definitely makes it much more actively engaging than the typical "set up your towers and watch it play out" style of game.
I will say perhaps the balancing could use a bit of improvement, only because I managed to beat the game without realizing there was a shop (totally my bad, I accidentally skipped that bit of tutorial text). I didn't acquire any upgrades during my playthrough and I was still able to beat every level. Even without the shop though the game was still engaging and enjoyable, very well done!