There are two versions of the game. The Mega Drive/Sega Genesis version and the Sega Saturn/PlayStation version which features CGI cutscenes that tell the game's story and some different levels that require more powerful hardware such as the Jurassic Park bonus level or the old west bonus level which are absent from the Genesis version of the game. On the other hand, some levels from the Genesis version like the one set in Hell or the one based on the Alien movie franchise are not present in the PlayStation version of the game.