Thank you for those super kind words :D
We had a tonne of fun working on the game, and making the gunplay feel juicy and impactful! When balancing the upgrades we leaned more towards over the top effects and power, as oposed to fairness, and we think it's turned out quite fun.
You're definitely right about the upgrades. It needs something extra in order to make the whole turret building process slightly less passive. We're currently thinking about what we can do for that!