I loved this one, it was fun and very engaging until the end
I solved the "game too difficult" problem by using the power of unethical warfare, if you keep all your units in the wood layer safe by using all resources to defend only that floor (filling it dozens of soldiers and later archers), then you have virtually infinite wood which means you can just spam harvesters and don't worry about them dying because its a net positive anyways.
Also, if you lay out the units across the map very spread out, the enemies of the second and third layer are too slow to kill them effectively, a harvester can get a lot of food before dying just because the enemies take forever to reach them, so you can just spam miners and harvester and don't even care if they die since they're so goddamn cheap and they mostly pay for themselves in the form of safety for the first layer
The fact that the game have this many mechanics to exploit in such a short development time is very impressive, good work. I would love that you can select the units with the number keys so I could spam them even faster in the late game lmao