The Engine Room is the main building on your Warship. Warship battles' results depend on the number of Engine Rooms remaining on each player's warship at the end.
The more Engine Rooms you destroy, the greater your chances of winning.
If you destroy all the Engine Rooms, remaining buildings will explode.
You can have from 2 to 7 Engine Rooms on your Warship. The Warship starts with 2 Engine Rooms, and additional Engine Rooms are unlocked through the Tech Tree, and require a certain Tech level and Headquarters level.
Unlocking a new Engine Room changes the play area of the Warship, changing landing zones and expanding the area upon which players can place buildings.
A Warship battle is decided by three criteria, the first being the total number of Engine Rooms remaining at the end of the battle. Keeping Engine Rooms well-defended will allow you to win on this criteria.
At lower levels, where Warships are often completely destroyed, keeping the Engine Rooms spread out can stall attackers' time and allow you to win on time. However, if an Engine Room is poorly defended, players can send a small amount of troops to quickly destroy it while using the remainder of their troops to attack the other Engine Rooms at the same time.
Engine Rooms do not take indirect damage from destroying buildings.