Let's bring back wall(for ground battle only)
To build walls, it's using a certain amount of house raw material
I think it should be able to hold at least 50Billions damages to make it worth or maybe 100billions to make it more interesting
Iron dome for Air Defence? to build it, need house raw and air weapon Q5. technically it's just another wall but for air battle only.
Able to hold 3 or 5 million damages for now.
In the future for sure need some adjustment due to strength growth and air rank