I definitely agree. The turret vs mob ratio is incredibly imbalanced. The upgrade rate is too much, as well as the shake.
I updated the game just minutes ago. I've added some minor but helpful changes to the game such as the ability to see the tower's range, the "formula of experience needed to level up" thing you mentioned (we were thinking the same thing!) for increasing the monsters' health per wave, some info about the towers stats, limit on tower upgrades, and some minor system balances.
I would definitely love to add some kind of tower ranking thing that makes the tower seem menacing as you upgrade them. :33
BTW: I made the gameplay screenshot that you sent here as one of the screenshots of the game :) Really made me hyped you made it that far!!! :D
Wow! Thanks! if you need someone to test your game just DM in discord(Panch). I am in the GWJ discord also. Good luck to the team and to the game!