Nautilus is a 1982 game for the Atari 8-Bit Computers that introduced unique firsts to the industry: the first Split Screen game, and the first Asymmetric Multiplayer game. That's right; while Nintendo invented and popularized the term Asymmetric Multiplayer, it was around 30 years before the Wii U!

There are one or two players. Player One (or the Computer) controls the Colossus, a ship on top of the ocean, on the top half of the split screen, and Player Two controls the Nautilus, a submarine who can travel freely underwater on the bottom half of the split screen. Their play experience is totally different.

The titular Nautilus is given the job of destroying an underwater city by shooting it down, and collecting the energy cores within. The energy cores also add fuel to the Nautilus. The Nautilus also must avoid things that have been dropped in the water to kill it, such as depth charges and homing bombs, and optionally (they can be toggled on/off or changed in difficulty levels), separate homing bombs that spawn on their own and seek it on higher difficulty levels, and lasers that turn on and off underwater and block the Nautilus's path. The Nautilus can rise to the surface to attack the Colossus directly. If the Nautilus is damaged, it sinks to the bottom of the ocean for a few seconds before rising and regenerating.

The Colossus is given the job of transporting a repair crew from the base on the right side of the map to the left side, which then rapidly repairs the underwater city. If the Nautilus happens to be where the city is when it regenerates, the city takes precedence, and the Nautilus takes damage equivalent to a kill. The Colossus also has to contend with a helicopter that drops small bombs into the water, and possible attacks from the Nautilus.

To address balance, the game has multiple difficulty levels, all of which tend to make things easier/harder for the Nautilus but not so much the Colossus. The difficulty affects things such as spawning homing mines that seek the Nautilus, the addition and speed of a helicopter that drops bombs which can hit the Colossus, the speed of the Colossus's underwater attacks, the existence of non-existence of underwater gates that open and close, and the score multiplier for how many points the ship gets for repairing the city.

This game contains the following tropes:

• Asymmetric Multiplayer: The first video game ever to do this! One player is a submarine, the other is a ship. The submarine can move in all directions, while the ship can only move side to side. The two players have vastly different goals, and even differently sized portions of the screen. The two players could hardly play more differently.
• Death Is a Slap on the Wrist: Both players have infinite lives. Death for the submarine means sinking to the bottom for a few seconds, then rising back up with full fuel. Death for the ship means being sent all the way to the right, the ship's home base. Essentially, killing the other player slows them down a bit and nothing more.
• Deadly Walls: Only a problem for the submarine. Touch any wall and you crash. The ship doesn't have this problem, as it can only go left (to recharge the city) or right (to collect a new charge).
• Destructible Projectiles: One of the first of its kind. The homing mines that chase the submarine can be shot down.
• Difficulty Levels: You can change two difficulty levels which affect how hard things are for the submarine or the ship. The ship might have to deal with a helicopter that flies by and drops bombs, at different speeds. The submarine meanwhile might have to deal with increasingly fast homing mines, and faster and more depth charges dropped by the ship. Electric gates that turn on and off can be toggled, and a score multiplier for the repair of the city can be applied for the ship.
• Emergency Refuelling: The submarine has a fuel limit that is continually draining. Running out of fuel means instant death, but the energy cores stolen from the city also refuel the sub.
• Enemy-Detecting Radar: A primitive form of this. Both players have a sonar-like sound playing that changes in tone when they both occupy the same vertical space. There's also an arrowhead on each screen representing the other player's horizontal position being to the left or the right.
• Homing Projectile: The ship can drop mines that chase the submarine, and their speed is affected by the difficulty level. On higher levels, they can be super fast!
• No Plot? No Problem!: In both the game and the instruction manual, there is literally no plot. No reason given for why the Nautilus wants to destroy the city and why the Colossus must repair it.
• One-Hit-Point Wonder: As is common for the era, both players are dead in only one hit.
• Protection Mission: Of a sort. The ship must defend the underwater city, in the sense that it must not only attack the submarine but also regenerate the buildings if they're destroyed.
• Split Screen: Also the first video game ever to do this too! Ship gets the top, sub gets the bottom. The top half of the screen is also smaller than the bottom half due to the ship not needing to see as much in order to know what's going on.
• Timed Mission: You get to set the number of minutes from 3 to 9, but both players compete to destroy and defend the underwater city until time runs out.
• Underwater City: The game is literally about a submarine trying to destroy an underwater city, while a ship must protect it.