Tankmen sunken battleship is a au of tankmen where the enemy army successfully accomplished their goal, which in this universe in breaking the dam which kept the area from flooding, essentially causing the end of the world. John, Steve, and skittles do manage to survive this. The difference in design is due to their damage from the flood. Skittles never knew this was his army’s goal, and when he finds Steve and the captain, he joins their new army of survivors, however, there are a few survivors of the enemy army as well, and they decide to make a army with the goal of destroying the captains army.

The environment is even more destroyed and desolate, and some areas are completely underwater, however the tankmen can breathe underwater with their gear.