Seems like a good start. Gameplay is very similar to other hover over to kill enemy games, but with more upgrades. I like the visuals, gets that neon vibe without being too hard on the eyes. Here are some suggestions for changes:
1: Rounds are way too long. Add more upgrades to bring it down to 30-45 seconds.
2: Bosses are horribly unbalanced. They either die instantly, or kill you instantly. I can't even reliably use ranged abilities because it usually spawns within my range.
3: Yellow currency seems to do nothing, despite being available from the beginning.
4: Purple currency is too rare. I have no more red and blue upgrades, but I can only do A purple upgrade once every 5 rounds. Still not sure how I get it since nothing drops purple balls. I'm on prestige 21, and it would take too long to make progress, so it's not worth continuing.
5: Does dropping your red currency into the power grid do anything? I think it might be responsible for the title at the top changing, but I can't be sure.
6: Can you make it so active ability is used on click instead of or as well as space bar? Perhaps make space bar stop your movement instead to make it easier to aim at something that can one-shot you without ramming into it.
7: I am not sure if enemy projectiles are too weak, or just do nothing. I can stand on top of projectiles without them affecting my health or armor, so there's no reason to even try dodging.
8: Do the teal hourglasses sometimes drop teal currency? They never seemed to drop anything, but I sometimes mysteriously got teal currency.
9: Perhaps add a movement speed upgrade?
10: Perhaps make drops combine with nearby drops to reduce lag?
11: Drops and enemies shouldn't spawn off screen. I spend way too much time scouring the edges to make sure I am not missing a ton of things I can't see.
12: Why do purple enemies drop blue currency instead of purple currency? Especially since I had no blue upgrades left by the time they appeared.
13: Perhaps add an upgrade that will spawn fewer but stronger enemies. This will also help with performance.