''Sewer Shark'' is a first-person rail shooter game, the first video game for a game console to use full-motion video for its primary gameplay. It was originally slated to be the flagship product in Hasbro's NEMO video game system, which would use VHS tapes as its medium. However, Hasbro cancelled the NEMO, and Digital Pictures later picked up the game for the Sega CD system. Sewer Shark was one of the first games to come out for the Sega CD - shortly after its release in 1992, Sega began to include a copy of this game with each Sega CD unit, making it one of the most widespread games for the system. It was later ported and released for the 3DO in 1994.

Storyline

Sewer Shark takes place sometime in the future. The player is a rookie pilot in a band of "sewer jockies", whose job is to travel through a vast network of underground sewers to exterminate various dangerous mutated creatures to keep the sewers clean of contaminants for the resort area of Solar City, an island paradise ruled by the evil Commissioner Stenchler (Robert Costanza). The player's co-pilot, Ghost (David Underwood), evaluates the player's performance throughout the game, while a small robot named Catfish scouts ahead and gives directions. Your quest is later assisted by Falco, a female jockey who believes that there is a hidden route to the surface, but her snooping angers Stenchler and she is captured. The eventual goal of the game is to reach Solar City by blasting enough creatures to make it through the tubes, following a "crazy looking thing" who guides you in the later missions.

Gameplay

As in other rail shooters, for the most part the ship flies itself, leaving the player to move the crosshairs on the screen and shoot ratigators, bats, scorpions and moles as they appear. Along the way, Catfish will give a series of coordinates (3, 6, 9, or 12) that the player must follow, under the risk of making a wrong turn and crashing into a wall. Shortly after receiving directions, the player will come across a series of turns - in the Sega CD version, by pressing 'B' and moving the D-Pad in the desired direction as the corresponding turn appears. Interspersed throughout the sewers are recharge stations - a light on the ceiling will indicate to the player which direction to turn to replenish the ship's energy. In later levels, the ship will occasionally pass through high concentrations of hydrogen which the player must have Catfish detonate.

Every now and then, Commissioner Stenchler (who is notably always eating, even when surfing) will check in on the player and give his own evaluation of the players' progress. His comments will depend entirely on the performance in the tunnels - the more ratigators the player kills, the better their rating will be, eventually prompting for a call sign change and a promotion ("A clean sewer is a happy sewer!"). As the player gains Ghost's trust, the extent of Stenchler's evil will become more and more apparent, until he's actively trying to kill the player.

Production

Sewer Shark sought to be something only a few games had been before: An interactive movie. At the time of its production, people were just beginning to realize the potential of CD-ROM technology to bring richer, fuller game experiences to the market. And while the Turbografx 16 was the first video game console to have a CD-ROM drive, the Sega CD was the first console to bring CD-ROM games into the mainstream.

The Sega Mega Drive/Sega Genesis console and the Sega CD add-on module were a formidable combination for their time, but even they were limited in their capabilities. For example, the CD-ROM drive was a single-speed drive, capable of transferring only 150 KB of data per second - between that and the limited display capabilities of the Genesis (64 colors on-screen at any one time out of a palette of 512 colors total), it was no easy task producing a game based on full-motion video. The video and audio had to be highly compressed, and a lot of work went into the video codec, a custom-written algorithm that worked very much like the later MPEG standard. By today's standards, the video quality was quite low, but for its time, this was a major breakthrough in game presentation.