There are 25 stages in the game, including bonus stages. Each series of five generally contains one of each type of mission. The fifth are generally the boss stages. The bosses are a sea serpent (as seen on the cover), a giant crab, a giant squid, a red and black version of the sea serpent and a giant shark. The game uses a powerup bar similar to the Gradius series. Powerup pods are collected to move the selector to different powerup items. When the desired powerup is highlighted, the player can select it, after which the menu returns to an unhighlighted state. Menu options are "Turbo" (increase the speed of the boat), "Fire" (increase the number of bullets the primary gun fires), "Speed" (increase speed of shots and rate of fire), "Missile" (improves missiles) and "Force" (a force field around the boat plus replenished health). The speed boat used for game play starts with a single gun which can be upgraded to a quadruple spread shot. Missiles can also be added to the boat's arsenal and can be upgraded to heat-seekers. Between stages which are not connected by water, the Cobra Class has a helicopter style propeller that extends from the roof of the cabin. However, this flying state of the boat is never used in gameplay. The boat has a 12-point damage bar which can be reduced by contact with obstacles or enemy fire.
