Fun Concept, it takes a bit of time getting used to but feels good once you pull it off. The only thing I found difficult is the pacing, it goes from 0% to a 100% within the first 40sec.
Nice Gameloop! It's easy to understand and I was constantly looking which turret wasn't needed anymore, to switch on the ones that were beneficial!
The style and theme were a nice touch. Also, the initial pacing was good and gave plenty of time to discover the mechanics and turret types (without feeling like a slow start).
I did at one point think you'd be able to fix the batteries as for me the enemies became quite indestructible around 550.
