Well, it was just fun to develop and I always wanted to do something with zombies. For me it was also some kind of exercise as I need to create this sort of AI in a different project later. Regarding gameplay, It was more important that it's working bug-free than balancing it. Regarding the theme, i just didn't wanted to do something with corona, toilet paper, hospitals, super markets, social distance. It's up to you how you interpret this.