Use your boat to bump away enemy boats that are entering your screen.
The enemies trying to infiltrate your water are submarines, once they pop out of the water they will shoot and have they have no mercy.
As long as submarines are in the water they will not be able to shoot torpedoes at you so these are not a threat.
The longer you play, the more enemies will be coming to attack you, also enemy airstrikes will be called in and try to bomb you from the top.
Try to survive for as long as possible and collect as many bubbles as you can. These bubbles can be used to buy new and iconic ships.
But be quick because enemies can pop those bubbles with their torpedoes!
As the game progresses the bubbles will have more value so try to aim for a long run.