Pacific is an arcade adventure game in which players control a sea diver searching for the lost treasures of Atlantis.
The game involves crossing screen after screen, dodging the deadly fauna and going as deep as possible. The player is equipped with a gun with a limited number of ammunition and an oxygen tank which needs periodic refills. There are several useful items scattered around, like ammunition, oxygen pumps, powder kegs that can be used to create holes in the coral reefs, and sextant which display a map of the player's surroundings and the current depth.
The ending of the game changes according to the gender the player has chosen at the beginning of the game.