Waterworld is an adventure game that was originally released on the SNES in 1995. It was developped by Ocean and went on to be released on multiple platforms such as the Virtual Boy. Although it is considered as a licensed game, it's only loosely based on the movie.
The game opens up with text telling you about the universe you're about to explore. This is actually one of the only indications that the game has anything to do with the movie:
The Sun, for millions of years the source of life, but for one planet the source of it's demise.
The temperatures climbed, the vast fields of ice at its poles melted and the oceans rose.
Centuries later, few people remained on this planet once called earth.
The only remaining pockets of civilisation are floating islands of debris called Atolls.
You play as the Mariner and fend off Smokers but that's about all the game has in common with the movie.
Note: "it's" in the first line is a spelling mistake that the developers made.
The game alternates between 3 different gameplay phases: some levels have you piloting a boat, others have you doing some platforming and then there are the bonus stages:
-Boat levels: You control a sail boat and must fend off Smokers who are riding jet skis, planes and motor boats. They're attacking your Atoll and you must destroy them with your missiles. You must also save drowning civilians.
-Platforming levels: Here you take control of the Mariner and must kill all the smokers to move on to the next level. You start off with a machete but can get other weapons such as a gun off enemies you've killed. You always play on the exact same level as you're always defending the same Atoll.
-Bonus levels: you unlock these after completing a boat level. It consists of you swimming underwater, trying to get bonus items before you run out of breath. If you run out of breath while underwater, you automatically lose all the items you had collected. These items get you points that you can then spend in the in-game shop to upgrade your ship.