Its animated opening shows pumpkin-headed Dennis deliver the infant Devil in a cage to his master, the resident Mad Scientist Dr. Knarf. The latter is initially annoyed as he was just about to dissect a helpless anthropomorphic eggplant, but soon decides that cutting a cute Devil into "teeny weeny little pieces" is even better! Luckily, our Devil manages to both escape his clutches and wreck the lab with a poorly stored bottle of nitroglycerin, the resultant explosion knocking the Devil all the way into Jersey.
Many years have passed, and Dr. Knarf finally recovered from the damage inflicted on his lab, and was able to finish his experiment to create an army of mutant plants to kidnap Jersey's residents. However, the Devil has now grown up into a defender of Jersey, and is there to rescue the citizens and thwart Knarf's plans.
This game contains the following tropes:
- Adaptational Heroism: Instead of being the evil creature it is in folklore, this version of the Jersey Devil is a hero.
- Airborne Mook: You'll regularly encounter flying insect enemies, complete with a very annoying mosquito-like whine.
- Ambiguous Time Period: While the bulk of the game is ostensibly set in modern times (i.e. the late '90s), the Distant Prologue is a little bit unclear; Jersey Town's growth from a small town with a population of less than 1,000 to the bustling Jersey City in the transition to the present day implies a Time Skip of at least several decades (and that's assuming it had a ridiculously quick urban growth), yet Knarf, who was already middle-aged-looking prior to the skip, doesn't appear to have aged all that much the next time you encounter him.
- Art Shift: The intro sequence is hand-drawn animation, while the in-game cutscenes are presented using the game engine.
- Cerebus Syndrome: Inverted; the game's opening, which shows the resident Big Bad about to dissect cute defenseless critters for fun, is a lot darker than that of a typical mascot platformer, and also the darkest the game ever gets. For the rest of the runtime, Dr. Knarf contents himself with merely kidnapping Jersey's citizens and calls it a needed break from the boring routine of their lives. In the end, he is sent to jail after being defeated and everyone is happy.
- Dark Is Not Evil: The Jersey Devil has black and red eyes, is a devil, and has purple bat wings, but is a good guy.
- Defeat Equals Explosion: All of the enemies defeated by the devil instantly disappear in a puff of smoke.
- Dies Wide Open: JD keeps his default expression upon losing a life in the European version, producing predictable results.
- Down the Drain: The level "Sewer Port" contains a section in the sewers themselves.
- Evil Laugh: The villain, Dr. Knarf, is quite fond of ending his gloating speeches with one. He also regularly laughs during his battle.
- Flash of Pain: The Devil flickers for several seconds whenever he gets hit.
- Flat Scare: The now-grown-up JD does this to Dennis in the intro cinematic—it's worth pointing out that this is the only sound he's heard making in the entire game as he's completely mute otherwise.
- Good Is Boring: The motivation of Dr. Knarf, as stated in his ending monologue:''Well, well, well. Seems like this beautiful little city has fallen back into its usual peaceful, boring, casual life. Enjoy it, stupid little citizens, because I'll be back!" (crawls out unharmed from a lava pit he fell into after getting defeated by the Devil, only to get arrested immediately after.)
- Heroic Mime: The Devil never speaks; pretty much all the voice acting in the game comes from Dr. Knarf.
- Losing Horns: Heard every time you lose a life.
- Mad Bomber: The pumpkin-headed enemies attack by spamming multiple cartoon bombs at regular intervals. Luckily, both their throw range and the explosion range is so pitifully short that they are easy to deal with regardless.
- Molotov Cocktail: Dr. Knarf throws these from atop a floating platform during his boss fight. You need to deflect them back at him.
- Not Quite Flight: The Devil has a pair of wings on his back, but they are only large enough to allow him to glide down.
- Purple Is Powerful: The Devil is all purple.
- Smashing Hallway Traps of Doom: A very literal example of a hallway with multiple ascending and descending doors that all have spiked edges.
- Spin Attack: The titular Devil can spin around to smack the enemies with his tail.
- A Winner Is You: The European version of the game simply cuts straight to the credits after JD flies away from Knarf's now-destroyed laboratory.