Could you add a system to view your stats? and the things the monsters get?

Fun game overall, but there is no end?

I do like the concept, but it got boring once you got a few upgrades that can essentially one-shot all the enemies, this is the most I can give for feedback:

Picking the wrong upgrade for the second wave will cause a game-over even if you try your best. I'd say at the start of the game, either have them attack slower or be killed in one hit.

Being able to hold the attack button and hover your mouse over the enemies isn't as engaging than figuring out when to click at the right-time.