This is a very interesting concept and I enjoyed the game a great deal. Got a lot of feedback, not bc. the game is bad, rathe rbc. I played quite a while and thought it's good.
Food is by far the most important ressource, as if it runs out everything comes to a halt. Effectively food shortage can kill you, if all your lumberjacks or miners die and you can't make a comeback, if you don't have enough resources.
I think it's bad that you can't remove buildings, with a slow and methodical approach this would be very necessary, as you can't really reposition anything except if the zombies kill it.
I also think it's bad that the amount of zombies is just rising and they literally don't move, as it means late rin the game you are only spamming barracks with the hope they kill off the zombies unless... you build shelters, as they pretty much kill the zombies.
Also if the zombie tikck is high, it really starts on the processor, it's a quite calculation heavy game and might need some optimization, especially in the areas where no zombies are anyways close, calculations probably could be driven back a lot.
Also the algorithm creating the map would need some check if there are zombies which can't be reached, as the game can't be completed.
And I think it's also a bit to motion heavy to always select a new building after placing one, as there ar enot hotkeys.
Moving around the map maybe also should work with rightclick holding.
That's all I can think of, really happy that I stumble dove rit. Loved the concept.