Fathom is a 1983 action-adventure game published by Imagic and designed by Rob Fulop. It was the last game Rob Fulop would design for Imagic, and one of the last games Imagic would publish before its closure. Fathom was initially released for the Atari 2600 in August 1983. It would later be ported to the Intellivision, Colecovision, and TI 99/4A. The player controls both a dolphin and a seagull in order to collect the missing pieces of a broken trident and save a mermaid trapped at the bottom of the ocean.
The goal of the game is to free the mermaid Neptina, daughter of Neptune, who has been trapped at the bottom of the sea by the Titans. The player character is a shapeshifter named Proteus who must recovered the shattered pieces of Neptune's trident to break Neptina's cage.
The player starts the game in the form of a dolphin and can swim freely between several different ocean screens. The player has a limited amount of time to collect all three shards of the broken trident and return them to the mermaid's cage at the bottom of the map. As a dolphin, the player must collect all the seahorses that appear on a certain screen, while avoiding octopi and seaweed beds. Once all seahorses are collected, they can collect a starfish which will give them one piece of the trident. Collecting enough seahorses will also cause a bird icon to appear at the bottom of the screen. Returning to the top of the screen with this icon will allow the player to start controlling a seagull above the water.
As a seagull, the player must fly around a different set of screens above the water while avoiding black birds and volcanic eruptions. Collect enough pink clouds and more starfish will appear which grant the player one more trident piece each. Collect all three trident pieces and enough clouds to make a fish symbol appear at the bottom of the screen, and the player can transform back into a dolphin and swim down to Neptina's cage to complete a loop. Every time one game loop is completed, the number of screens on the game's map increases and the player must travel farther to complete their objectives. Once the player completes seven loops the game is over and a secret ending is revealed.
Fathom was designed by Rob Fulop for Imagic. According to Fulop, early development on the game began when game artist Michael Becker rendered a picture of a dolphin jumping out of the water. The game concept and gameplay were then designed around the image. Becker would go on to work as the game's artist, designing all of the game's graphics in collaboration with Fulop. This was highly unusual for the time; Fathom was the first project Fulop had worked on in which he had been responsible for none of the game's graphics.
In an interview with Computer Entertainer, Fulop said he designed the game to feel like players were controlling all of the characters in a cartoon and that the game was "designed to look more like a cartoon than any other type of video game." He also hoped that every time players would pick up the game, they would learn something new about it. Fulop described the process of discovering new things, then using that knowledge to discover more new things as "the hook to [making] a good game."
Later, Fulop would become frustrated with the way control of the dolphin would transition to the seagull. Fulop had wanted to create a more dramatic transition between the two gameplay states but doing so would have cut part of the dolphin jumping animation Becker had designed. This alteration was shot down by fellow game designer Dennis Koble and Imagic CEO Bill Grubb, and Fulop claims this incident caused him to sour on the game following its release.
The game contains an easter egg. Under the right conditions, the initials of the three developers for the game (Rob Fulop, Michael Becker, and Wilfredo Aguilar) can replace the rocks spewing from the game's erupting volcano. This is despite the fact that the developers' full names were printed within the game's packaging. According to Fulop, the easter egg was included because players responded well to easter eggs in other games and the 8 KB ROM used by the game had enough space for secrets.
Versions of the game for Atari 8-bit computers, Atari 5200, and VIC-20 were planned but eventually cancelled.
Fathom is frequently praised for its graphics and animation. Jim Clark of Videogaming & Computergaming Illustrated would call the game's graphics "wildly impressive, even beautiful", and E.C. Meade would describe the animations as "simply outstanding". Mike Wilson of The Logical Gamer would also praise the games graphics but describe them as comparable to previous good-looking games on the system.
When it comes to the gameplay, critics are more mixed. Computer Entertainer would give the game a perfect score in both gameplay and graphics, describing the game as feeling like a great adventure and commending the way the game expands with each loop. However, The Logical Gamer's Mike Wilson would describe the gameplay as boring once mastered and advised people to stay away from the game. Electronic Fun with Computers & Games would describe the game as "monotonous" and "tremendously dull". The gameplay is frequently compared to other Atari 2600 games such as Adventure, Dolphin, and Journey Escape.
Retrospectively, IGN would applaud Fulop's work on the game and declare it to be "perhaps his greatest achievement on the 2600". IGN would also heap praise on the game's graphics, describing them as beautiful and elegant. They would place Fathom near the top of their top 5 Imagic games for the Atari 2600.