As there are three main monsters, there are three stages: Dracula's House, Frankenstein's Castle, and Chameleon Man's Graveyard. The process of each level is to have a candle lit so that the magic sword is charged. Touching the charged sword upgrades Little Red's standard zap into a SuperZap for one shot only. This SuperZap is the only thing that can destroy the main monsters and they know it. They'll run from Little Red while he's charged and the higher the round count, the more effective their flight.
The stages are set apart by unique challenges and a rapid increase of the difficulty from one to the next. Candles are spent after a while and the magic sword requires a lit candle to bestow the SuperZap. Candles aren't replaced until a cloud has passed in front of the moon. In Dracula's House, there are five candles and the moon is permanently obscured. In Frankenstein's Castle, there's only one candle and the cloud loops across the screen. In Chameleon Man's Graveyard, there's one candle, a looping moon, and the Chameleon Man becomes immune to the SuperZap if he gets the time to change his skin's color to that of the field. Minor monsters that inhabit the stages also become more troublesome with each stage. The bats in Dracula's House are slow and not too bad. The werewolves in Frankenstein's Castle are fast and duck when being shot at, meaning they can only reliably be zapped while on the stairs. And the spiders in the Chameleon Man's Graveyard are fast and respawn elsewhere immediately. This means there's always a swarm of them to waste the SuperZap on. Furthermore, Dracula's House has warp doors that can always be used. Frankenstein's Castle has warp doors that can only be used sporadically, but also permant jump-down zones. The Chameleon's Graveyard has no shortcuts, but there are buttons to change the color of the field and influence which gates are up.
Supplementary material for Monster Bash includes the American flyer in which the Monster Bash arcade cabinet is a gift from Frankenstein's Monster and the Wolfman for Dracula's birthday, the Japanese instruction booklet which uniquely contains a mini-manga, and the promo video created by Gremlin. In the latter, a Mad Scientist introduces the Monster Bash arcade cabinet as his latest creation.
Monster Bash has yet to be released for home console, but the 1986 game Ghost House is a Spiritual Successor in that it turns the stage Dracula's House into one big game.
Monster Bash contains examples of:
- All There in the Manual: The main character is only named in the flyers. He's Bashman in the Japanese flyer and Little Red in the American flyer.
- Attract Mode: While no one is playing, a sequence is run in which Little Red introduces himself. He's chased off-screen by the three main monster, which then return and retreat to their own residences. Little Red follows them, touches the charged magic sword, and zaps them all into goo.
- Bat Out of Hell: The bats in Dracula's House serve Dracula. Or they don't but Dracula lets them crash because they improve the spooky atmosphere and kill heroes that come to kill him.
- Breaking the Fourth Wall: During the attract mode, Little Red walks onto the screen, turns to the audience, waves and elaborates that he's the hero. It's the only speech bubble in the entire game.
- Creepy Cemetery: Chameleon Man's Graveyard is the third stage. It's home to the Chameleon Man and lots of spiders, all of which do One-Hit Kill Collision Damage. Gates in red, blue, and green litter the area and only the gates that match the color the field at that time is don't block passage.
- Frankenstein's Monster: Frankenstein's Monster, or just Frankenstein, is the main monster of the second stage, Frankenstein's Castle, which he graciously shares with werewolves. His design mirrors the Universal one with green skin, a tall forehead, and so on. Like Dracula, he has no noteworthy abilities beyond Collision Damage.
- Haunted Castle: Frankenstein's Castle is the second stage. It's home to Frankenstein's Monster and lots of werewolves, all of which do One-Hit Kill Collision Damage. There are warp doors that work only when they're blinking and there are spots where one can jump down to a floor lower but not go up a floor.
- Haunted House: Dracula's House is the first stage. It's home to Dracula and lots of bats, all of which do One-Hit Kill Collision Damage. There are warp doors to easily move from the lowest floor to the highest and back.
- Hollywood Chameleons: The Chameleon Man's main trick is to steadily change his skin's color into that of the field. He never becomes invisible (in fact, the final step turns him a distinguishable black), but he does become invincible. To defeat him, Little Red has to change up the floor color every so often so that the Chameleon Man has to start all over with his own color changing.
- Hunter of Monsters: Little Red goes on his own to fight and end three powerful monsters: Dracula, Frankenstein's Monster, and the Chameleon Man. No reason is given why he does that, but he assures the audience in the Attract Mode that he's the hero, so he's probably doing the right thing.
- I'm Melting!: After a main monster is hit with the SuperZap, they go down melting.
- Mad Scientist: In the promotional video, a mad scientist introduces himself as the creator of the Monster Bash arcade cabinet.
- Monster Mash: The three great of the mash are here as the enemies of Little Red: Dracula and Frankenstein's Monster act as main monsters and werewolves act as minor monsters. The oddity is the Chameleon Man, who is the third main monster instead of an established figure like the Wolfman. The flyers that come with the game as good as ignore the Chameleon Man and pay more attention to the fact the game contains werewolves.
- Ornamental Weapon: The magic sword isn't useless, but it's not used as a sword. When it's charged, it bestows a single SuperZap on Little Red to defeat the stage's main monster. No explanation is given why the SuperZap bestowing object specifically is a sword.
- Our Vampires Are Different: In the Japanese version, the game's vampire is only identified as Vampire, but based on his looks he's likely still meant to be Dracula. Whatever the case, like Frankenstein's Monster, he has no noteworthy abilities beyond Collision Damage.
- Our Werebeasts Are Different: There's the werewolves in Frankenstein's Castle for one, but more important is the Chameleon Man in the Chameleon Man's Graveyard. It's not certain that he's a werebeast, because there's no backstory provided for him and he's not based on older lore, but as he takes the place of the Wolfman in the usual Monster Mash trio he probably is some manner of werebeast. Unlike fellow level bosses Dracula and Frankenstein's Monster, the Chameleon Man has not one but a grand two abilities to defend himself. For one, he has a long tongue for ranged combat. For two, his skin gradually takes the color of the floor and when the two match he's indestructible.
- Our Werewolves Are Different: Werewolves hang out with Frankenstein's Monster in Frankenstein's Castle. The moon is uniquely full during that stage, suggesting that the werewolves wouldn't be in wolf form or would be weaker were the moon in any other fase. They're intelligent enemies who duck when being zapped at to avoid the bolt.
- Public Domain Soundtrack: Toccata and Fugue in D minor, BWV 565 is used in the promotional video for the game, which takes place in a mad scientist's laboratory.
- Shaking the Rump: After getting one over on Dracula and Frankenstein's Monster, Little Red taps his heel and waves his arms while facing the player. After defeating the Chameleon Man and thereby winning the round, he faces away from the player and shakes his behind in triumph.
- Spiders Are Scary: Plenty of spiders inhabit the Chameleon Man's Graveyard. Up to two can be permanently destroyed by Little Red, the Chameleon Man, or even each other, but any more will immediately respawn.
- Weird Moon: The moon is shown to be crescent at Dracula's House, at Chameleon Man's Graveyard, and during the attract mode. The moon is full, however, at Frankenstein's Castle, where the werewolves roam. It's possible that clearing each stage takes Little Red half a month, but it seems more likely something weird is up with the moon in that stage alone or in all of them.
