Fix The Upgrades
I upgrade my damage to near max, start upgrading my accuracy and charge, and put one more on the single shot in damage and it turns into some piece of shit that drains the energy in 4 shots. My other guns have no upgrades so I'm sitting there on number 3 with no ammo on my main gun and two useless other guns with a worm on my right and little land bastards jumping off the ceiling onto my face. I literally had one hit after the worm somehow got me, even though I jumped away from it, I barely kill it, have no ammo in my fucking single shot and get ripped apart by bastards that hit me from the top with no warning.
Fix the upgrades or add a checkpoint system. I shouldn't have to restart after 20 minutes of playing a quite boring defense game. The upgrades shouldn't make my gun into some shitty alien blaster that takes away all my charge in 4 bullets. Please make it something different, or make it check point after each generator is done. I know you must've put a lot of work and time into this, but next time add checkpoints or saves, and god damn it don't fuck with my gun to make it a charge consuming shit pile.