Operation Neptune, by The Learning Company, is a game developed for children aged nine to fourteen. As the company name suggests, The Learning Company designed PC games that were educational in execution while adopting kid-friendly cartoon aesthetics and simple gameplay that was good by the era's standards.
Operation Neptune puts the player in a submarine where, through arcade-style 2D gameplay, they navigate underwater sea caverns in search of pieces of a lost space capsule that is polluting the oceans. While ecological and exploratory in themes, part of the core mechanics, and thus the raison d'etre of the game, were elementary level math problems.
A group of astronauts and scientists working on a distant planet have sent back a space capsule. However, upon sending it back to Earth, the capsule broke up and dispersed in the ocean. Along with the capsule are data cannisters which outline the story of the scientists, which is revealed as the cannisters are acquired. The pieces of the capsule are also leaking some of the toxic chemicals (Substance X) that were sent back to Earth, and "Operation: Neptune" is begun to recover these dangerous artifacts. Substance X, it is discovered, is matter that has a greater energy potential than even Uranium, and if handled incorrectly, could spell disaster for the Earth.
The player is required to navigate underwater sea caverns while avoiding various sea life and obstacles, such as underwater volcanoes and sharp rocks. Sea creatures can be stunned temporarily by hitting them with ink pellets, akin to the defense mechanism of an octopus. This harmless combat is in step with the Learning Company's track record of developing politically correct games. The final sector in the game is an exception to this; the Substance X-mutated sharks found there shake off the effects of the ink pellets almost instantly, requiring the player to avoid, rather than defeat them.
The math problems in the game are elementary level in difficulty, ideally suited for the target demographic. They come in two varieties: one type that relates to the operation of a submarine (a ballast arithmetic problem) and one type that involves inputting using math to acquire a code for the combination lock at the end of a sector.
There are five zones in the game: Dragon Reef, Fossil Trench, Limestone Ridge, Sea Forest, and Hammerhead. Each zone has 3 sectors. Each sector will offer a variety of obstacles, three random math problems, one math problem to open the data cannister, and a final math problem to access the underwater supply station at the end of each sector. The sole exception to this structure is the fourth sector in Hammerhead, which contains no math problems and requires a no-hit navigation of obstacles.
Life is measured in Oxygen and will be depleted as obstacles are touched or a math problem is answered incorrectly. Zoom the Dolphin will replenish Oxygen should the player catch him when he swims across the screen. Again, the final sector is an exception to this and all Oxygen will be depleted with a single contact with an obstacle.