The Sega (Mega) CD version of the game was a port of the PC Engine version, but was made specifically for the western market with localized text and dialogue. As a result, a few additions and changes were made to the game to make it more marketable. -The date of the Catastrophe was moved five years ahead of the original Japanese version from 1991 to 1996 to make the storyline up to date for western audiences unfamiliar with the original version at the time. As a result, all the other dates mentioned in the game were moved five years ahead as well to keep them consistent. -A new scene is added to the opening intro where Gillian reveals to Jaime that he had become a Junker. The scene was taken from the prologue manga (comic book) that was included in the game's manual, but the Sega CD version is the only version where the scene is rendered in-game with full voice acting. -Many keywords and names were changed. Joy Division (the black market store) became Plato's Cavern. Alphaville (Neo Kobe's computer network) became Alpha-One, the Tricycle (the flying vehicle) became a Turbocycle and so on. -Several graphics and scenes were redrawn or changed. The outfit Katherine (Katrina) wears when Gillian first meet her is different, Jean-Jack's torso is facing front when his headless body is shown, Elijah Madnar's potrait in the church was changed to look more like Tomiharu Kinoshita's artwork of the character (as a result, all of his flashback scenes in the game were redrawn to feature him with long hair). The naked snatchers's eyes were changed from red to green (to avoid copyright infringement with the Terminator films) and light brown highlights were added to their bodies, giving then a more detailed appearance.
- Many of Gillian's lewd sexual comments and actions (including a scene with a porno tape) were edited out from the Sega CD version. Moreover, Katherine's age was changed from 14 to 18 due to the fact she had a nude shower scene in the game (in the very same scene, Gillian's head obscure the player's view of Katherine's behind and her breast were redrawn to give them a more mature appearance).
- The exposed breast of the Lisa Nielsen snatcher is covered-up in the Sega CD version and Alice (the dog) no longer twitches during her death. -A puzzle which requires the player to input Katherine's measurements was changed to simply pinpointing the shape and location of Katherine's birthmark. -A few new angles were added to certain scenes. This include a close-up of Gillian's apartment and new shots during the scene with Elijah Madnar. -The Sega CD version is the only version of the game that was compatible with a light gun. It supports the Justifier light gun which came with the Lethal Enforcer game. -The clientele at Outer Heaven were changed from parodies of popular sci-fi characters like Cornelius, Guyver and C3PO in the previous version to Konami characters like Simon Belmont (from Castlevania) and Goemon from the Mystical Ninja series. -More puzzles were added to Act 3 and a few new shooting scenes were included prior to meeting with Jaime. As a result, you can actually shoot Jaime when you reach her and get a Game Over. -And finally, a new scene featuring Mika and Katherine meeting Gillian and Jaime was added to the ending, filling a few of the plot holes left in the Japanese version.
