It's honestly difficult to find anything to criticize. It would be nice if I could carry as many weapons as I want, and swap between them when they run out of stamina? But then I came back for another run, and I realized that guns aren't power in this game. Healing is power. Healing, and a rusty crowbar you keep dumping resources into.
So the plan is for two zones the size of the Fields, huh? Four zones, more story, maybe an Endless Mode, and I could see this being moderately successful on Steam.