I think you would be happy with Great Midwest

Took some inspiration from Tactics, in that I wanted vehicles (no tanks, but a big rig would serve as your mobile camp) and the villain would be the Vault-Tec executive board, kidnapping people to harvest their organs so they could live forever

Though, the Executive Vault (or Vault X) would be built under Lake Michigan and you could just dump the lake into it to kill everyone if you were feeling inclined