Air-Sea Battle is basically a target shooting game where you shoot at targets on the screen. The different settings provide various targets and weapons with unique characteristics. In most cases, you are positioned at the bottom of the screen and shoot at targets at the top.
In games 1-6, you play as an anti-aircraft gun and shoot at aircraft. You have limited control over your shots, including selecting firing time, angle, and minor direction control for some settings.
In games 7-12, you are a submarine shooting torpedoes at ships above the screen. You can move left or right, but your torpedo's firing direction is restricted to straight up.
In games 13-15, you play as an anti-aircraft gun again, this time shooting gallery targets like clown faces and ducks. The controls are the same as in games 1-6.
In games 16-18, you are a ship firing Polaris missiles at jets flying above. Your ship moves on its own, and you control only its speed. When you fire, your missile's angle and speed depend on your ship's speed before firing.
In games 19-21, the situation is reversed: you play as a jet dropping bombs at ships below. The controls are similar to games 16-18, but from above.
In Games 22-27, one player controls a jet and the other plays as a ship in a two-player game that lasts for 2 minutes and 16 seconds.
The single-player mode pits you against a computer opponent that fires constantly. Your goal is to outscore them.