Get a friend and take turns. You can also play with anyone. Also owners of IOS and Android devices can battle together.
Here's how it works...
Select Two Player from the main menu.
You can either Start a Game or Join a Game.
Start a Game: give your game a name. If you want to make it private add a password. Don't forget to tell your friend the password!
Join a Game: Pick a game from the list of games. If it says "Open" then anyone can join. If it says "Private" then you need to know the password.
Once you both join the game, put your boats in the water and take turns until there is a winner!
