It had the same essential concept of the comic book, although Hobgoblin and Gremlin, initially the good monsters' comic relief, now appeared as villains, to the extent that Gremlin was a boss. Warlock sends out his henchmen, led by Spring Heeled Jack, Bigfoot, Kraken, Gremlin, and Medusa while Vampire and The Monster are watching TV in the Miles home.
They must fight their way through the upstairs and kitchen of the home, the street, and the sewer; they emerge in a construction site and an Orientalist garden before fighting Warlock at Monster Mountain, although that's not quite the end. Vampire and the Monster's abilities in the game are the same (though 2-player simultaneous action was an option)--an attack that can extend slightly beyond their bodies with a bit of a blaze, and they can make a double-jump from the height of their jump, something that has since become a common move in many video games. The remaining good monsters from the comics--Werewolf, Vampiress, Golem, Swamp Beast, The Phantom of the Opera, Jotun Troll, Invisible Man, Dr. Jekyll, and Mummy--made no appearance whatsoever in the game, although Werewolf did appear on the cover. Warlock and Minotaur were the only two monsters from series 2 to appear in the game. In the comic book, however, Medusa declared that by her count, Vampire's side had a majority, though all the other series 1 monsters were included as enemies in the game. Blemmyes appeared prominently on the cover, and the figure was distributed exclusively with the game, though did not appear in the game itself. It came inside the box, next to a smaller piece of styrofoam than NES cartridge boxes normally contained.