Nice! Calling it here.
Very neat looking UI and clean art work over all. The game chugs very hard on first instantiation of some effects due to shader compilation I think. The trick to get around this is to have a loading screen where you instantiate all those effects/shaders once so that it doesn't then stutter in the midst of action. This was my first time using Godot really in a long time and struggled quite a bit with the same thing. The web build shader compilation (on some machines at least, seemed to be slower on PC than Mac) really seems to be slow. But even if it'd be faster, it's not optimal to do it in the middle of the action when it will at least skip some frames.
Sounds too were good but some music really would have been needed. And there were some actions that weirdly had no sound. Enemies overall could also use some more "passive" movement sounds and even stuff like a warnings before a charge etc or something.
Sometimes it took ages to find the final enemies of a wave. Of course you could just stay still and wait for them to find you but you'd run the risk of getting ganked without any time to react. Some indicator arrows pointing at off screen enemies would help a lot. That same thing would make starts of rounds more fair as you'd have at least some clue on from what all directions you'll be swarmed at.
Guess I lied about that being my final run, went for another one but now at around wave 10 I can't find the final two enemies anywhere. I've been wondering around and even completely idling still for a good 5 minutes but nothing. Not fun really. And the same thing happened now a second time too. I had just one charger enemy left so as it was about to charge, I slowed down the time to trigger that very over powered mushroom powerup and the enemy just vanished not to ever appear again.
I find that the time slowing mechanic is maybe a tad bit too powerful (or recharges too fast after use or something). It kinda forces you into this awkward dual play mode of slow down & nuke everything and then kite around until you get your charge back. Then just rinse and repeat and hope you don't get stunlocked into oblivion after a slow charge ends. This strategy also makes quite a lot of the upgrades kinda moot. Like the shot speed (especially the rare one) seems awesome at first but with such a limited clip size, slow ass reload and the forementioned slowdown strategy, it's kinda pointless. So from all I've seen, it's basically just mushroom, ricochet, homies, clip size and finally slowness extension, damage reduction or maybe some extra hp (too much seems like a wasted cost) when nothing better is to pick.
But the constant disappearing enemies forcing you to a soft lock really detracts me from going for a better run.
Anyways, good job! 👍