In the game the player pilots a boat across the sea, randomly encountering groups of hostile sea creatures. When the boat snags something in the overhead map, the perspective changes to a side-view. The player's boat releases a diver who battles various undersea threats such as jellyfish, rays, and smaller sharks. Occasionally, Jaws will appear on the map in the form of its familiar dorsal fin breaking the water's surface. If players collide with Jaws' dorsal fin, they can momentarily control their boat in the side-view encounter in an attempt to attack Jaws with depth charges. Jaws will always collide with the boat and release the diver into the water. Jaws will also appear after a brief moment if the player snags something in the overhead map with Jaws nearby.
Items encountered include crabs (increases movement speed of the diver), stars (bonus points), and conch shells which are used as currency in this game. Equipment and upgrades are purchased by alternating between two ports on the map. The first port visit gives the player a receiver, which tracks the location of Jaws relative to the boat on the overhead map; the faster it beeps, the closer Jaws is to the player. Future visits to ports afterwards increases overall attack power against Jaws. Touching a hostile sea creature during the side view undersea encounters will kill players and penalize them with a power level drop by 1 (if they had upgraded their attack power), the loss of the tracking device, the loss of half of the conch shells accumulated to that point, and complete health replenishment for Jaws.
Killing a specific number of smaller sharks will trigger a bonus game. In this bonus game, an airplane travels back and forth in a side-view perspective and drops cannonballs on jellyfish, which assume formations and movement patterns similar to the enemies in the Challenge Stage of Galaga. Players can adjust the speed of the airplane, depending on what direction it is traveling. The player is rewarded the number of conch shells equivalent to the number of jellyfish killed divided by 3, rounded down. Hitting all the jellyfish awards 10,000 bonus points. An extra life is awarded for every 30,000 points.
The player can also find a submarine which appears at random places in the game map. The submarine is an upgrade with two weapons (torpedoes and depth charges) and much less inertia than the diver. The submarine is fragile, however, and one collision with an enemy will destroy it and release the diver (although this will not kill the diver).
Once Jaws' health has been reduced in the side view encounter, the game changes to a "first person" view of the player's boat. Players are given three charges for their strobe device to force Jaws to breach the water's surface. Timing is essential in order to force Jaws to breach at the proper distance from the bow of the boat. Players can also jut the bow of their boat forward at any time. In order to fully defeat Jaws, the player must jab it with the boat's bow at the proper distance when it breaches from the strobe device. This can be quite difficult and require much patience. Jaws makes random movements backward, forward and side-to-side which makes for a hard final kill.
Source: Wikipedia, "Jaws (video game)," available under the CC-BY-SA License.