The game originally started out as a Universal movie monsters fighting game, which would use the Street Fighter II engine. Though the final game still uses the engine, Universal did not want to license the monsters out, meaning the development team had to make completely new characters, which producer Alex Jimenez said took him about an hour to do.

There is evidence in the code of the arcade version that the two boss characters, Huitzil and Pyron, may have been planned as playable at one stage of development. There is an alternate color scheme for both of the characters that shows up if you are playing a mirror match, both characters are able to be played in Arcade mode though hacking (though Pyron can't fight the final boss due to a bug), both of the characters have their own endings, which are the exact same as their endings in the sequel, "Night Warriors: Darkstalkers' Revenge", though in a more unfinished state with the ending text just repeating "A" and the music not playing like it should.

Morrigan was originally a female vampire but the game's designer, Alex Jimenez, changed her into a succubus because they already had a vampire. Capcom didn't know what a succubus was but when Jimenez explained what one was, they were suddenly all for the change.

When Lord Raptor performs his special move, "Ultimate Undead", a small tune will sound which sounds strikingly similar to the introduction of Michael Jackson's song, "Bad".

The Japanese version features a stylized border around win quotes that was removed in the international version for unknown reasons.

The bottom corner of the Continue screen features advice to the player. These tips remained untranslated in the international version.

The game's data contains labels for player 3 up to player 8. It is possible that a mode reminiscent of the Tournament Battle variant of Super Street Fighter II (a special version that networked 4 cabinets together to allow for 8 player elimination tournaments) was considered at one point in development before being scrapped.

Lord Raptor's monster type is different across regions. In Japan he's known as a zombie, while internationally he's referred to as a ghoul.

In Darkstalkers: The Night Warriors, Huitzil has a fully-functional standing light kick which was never seen in any of the subsequent games. While the CPU never uses it, this attack can be performed by the player, although its slow startup and short range do not make it very useful. It can't be canceled into specials, nor does it have a rapid-fire capability. When Capcom Fighting Collection allowed Huitzil to be playable by conventional means, his animator Shisui said that this move was "so embarrassing that he wished it had never seen the light of day."

Huitzil's intro animation goes unused in the game in spite of being seemingly complete, thus making him the only character in the game to not have one. This intro animation would eventually be used in Night Warriors: Darkstalkers' Revenge.

When playing as Huitzil, it is possible to perform an unused Special Power Move where his arm turns into a laser cannon. In addition to having misaligned effects and incorrect colors, the move doesn't have a hurtbox, and once it is done Huitzil is frozen in place until he gets hit by the opponent.

The game files contains data for a second normal throw where Demitri bites his opponent. Demitri would later gain a throw similar to this one in Darkstalkers 3.

The game's files contain a pair of unused name labels, one for the life bar and another for the VS screen which read as "Franken" and "Frankenstein" respectively. These were likely abandoned names for Victor, the Frankenstein's monster-based character.