Darkstalkers

Darkstalkers was Capcom's next fighting game venture after the success of Street Fighter II. Featuring a Hollywood monster theme, eye-popping animation, and gameplay mechanics that would eventually become genre standards, it can be considered a milestone in the history of Capcom fighters.

Bosses
The characters Huitzil and Pyron are unplayable bosses in this first iteration of the series. However, there is ample evidence that they were intended to be playable at some point in the game's development.

By setting character select addresses (for player 1) or  (for player 2) to either  (for Huitzil) or  (for Pyron), both characters can be selected. The game will freeze when attempting to load the map demo prior to the Pyron boss fight if the player has Pyron selected, but aside from this they are nearly perfectly playable, with all moves able to be performed (albeit some with different commands than would be used in later games in the series).

Player 2 Colors
Both characters also have functional alternate color schemes for same-character matches, despite this being impossible in the game proper. Huitzil's alternate color scheme accidentally loads the palette for his lower body while jumping and one of his effect palettes into each others' slots, causing a rather strange look.

Endings
Upon completing the Pyron boss fight, both characters even have endings that will play, the same ones that would be seen in the sequel Night Warriors where they became playable characters. These endings lack music, and although the Japanese release has the proper text, the international releases simply display garbage strings of "AAAAAAAAAA".

Pyron Graphics
Pyron has an unused graphic for appearing in the group shot of the game's intro. Interestingly, Huiztil is actually present in this shot. It's likely that he wasn't removed because he and Victor are actually drawn into the backdrop rather than being sprites as the rest of the characters in the shot are. Thus removing him would require actually redrawing the backdrop. He also has unused 'defeat' graphics, as would be seen after a stage. As mentioned, he is not playable, and the game goes directly to the ending sequence after he is beaten.

Huitzil EX Beam
When playing as Huitzil, it's possible to perform an unfinished EX move by pressing Down, Down-Forward, Forward, then all 3 punch buttons simultaneously. In addition to having misaligned effects and incorrect colors, this move's incapable of actually hitting the opponent. The animation freezes after the beam is fired, meaning that Huitzil will become frozen in place, uncontrollable, until he is hit by the opponent. Some further graphics exist for this move, including an electricity effect and a Huitzil sprite with lighting similar to that seen in his Plasma Beam special.

P3-P8 Labels
Labels for up to 8 players exist within the graphic data. This is highly 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. It's likely that a similar mode was planned for Darkstalkers but never realized.

Franken/Frankenstein
A pair of unused name labels, one for under the lifebar during play and the other for the character select and VS screens exits. The former reads "Franken", the latter "Frankenstein". These are likely abandoned names for Victor, the Frankenstein's monster-based character.

Misc. Effects
Three unused effect sprites that seem to have no associated animation data.

Blood Pool
A pool of blood spreading out on the ground. Maybe it was intended for opponents who had been chopped in half on K.O.?

Water Effects
Rikuo's stage places the fighters in a shallow rainforest stream and accordingly replaces the characters' standard ground shadow sprites with special water effect sprites. In the finished game, only two types are used: a ripple effect for characters on the ground and a wavy shadow for characters in the air. However, several other unused effects exist: Small splashes, possibly for characters' footsteps. Large splashes, possibly for when a character lands from a jump or is knocked down. A dissipating ripple and upward spray, possibly for when a character jumps or otherwise leaves the ground.

Ground Effects
Two types of ground spark effects, each with 3 different sizes. Possibly intended for characters landing from jumps and hitting the ground after being knocked down. The 3 sizes might correspond to the 3 weight classes the characters are divided into.

Dust Clouds
A set of dust clouds in 3 different sizes, similar to those used when characters are sliding back from a hit in many other Capcom fighters. Again it's possible that the 3 sizes were to correspond to the 3 character weight classes.

Dust Trail
A dust trail animation exists unused, similar to but smaller and less elaborate than two other dust trail animations actually used in the finished game.

Orb
A strange flashing, undulating orb.

Pyron Projectile
Pyron's spriteset contains a pair of spiraling projectiles, one horizontal, one diagonal, complete with impact animations. Their intended purpose is unknown.

Huitzil Music Notes
A set of stylized music symbols exists in Huitzil's spriteset. The graphics are located near those for his one man band winpose (in which he produces several musical instruments and begins to play them in unison), so they were likely intended to be used with it.

Huitzil Hammer Head
A few stray tiles stored with those for Huitzil's Plasma Beam special appear to show his head transforming into something resembling the hammer mechanism of a revolver, complete with a range of motion for cocking and firing.

Huitzil Separated Parts
In this game, Huitzil is sprited in such a way that he is made of many separate body parts that are layered together to create a whole sprite. However, a separate sprite index containing each of these separate parts as individual sprites exists, likely for developer reference purposes. Included within these are rough draft versions of a few of the weapons used in his attacks:

Huitzil Jumping Medium Punch Spikes
A couple frames of Hutzil's jumping medium punch are missing a spike on the ball his arm has transformed into. However, his raw tileset and index of separated parts contain a couple unused spike sprites that seem to fill those gaps.

Huitzil Close Standing Hard Punch Arm
An alternate arm part intended for a frame of Huitzil's close standing hard punch exists unused. It makes the transformation of the arm a bit smoother.

Huitzil Standing Hard Kick
The weapon part used in Huitzil's standing hard kick is a rough mockup. A finished version can be made by combining other parts.

Huitzil Recovery Landing
A special animation intended for Huitzil landing after being hit in midair exists unused. Although his midair recovery animation actually does show his quadruped legs deploying, upon landing he plays the same animation he uses for landing from a jump.

Huitzil Breakfall
Interestingly, an animation that appears to depict Huitzl breaking a fall with his hands and righting himself exists unused, despite no sort of safe fall mechanic having ever existed in the Darkstalkers series. Even more interestingly, variants of this animation were made for Night Warriors and Vampire Savior 2 & Vampire Hunter 2, yet they still go unused in each.

Huitzil Slice Recovery
This unused two-frame sequence was intended for Huitzil recovering from a standing sliced-in-half animation. Here's how it would have looked in context.

Demitri Bite Grab
Demitri has unused sprites and animation data for what would seem to be a second normal throw, similar to the one he would later become able to use in the third game in the series.

"Demitori" Lifebar Name
Demitri's lifebar name graphic is actually misspelled as "Demitori" (a direct romanization of the Japanese phonetics). Apparently there was no time to actually fix the graphic, as the finished game employs a slapdash fix: the tiles are overlapped in such a way as to hide the "o". The misspelled name was shown as is in some pre-release promotional screenshots: The graphic was given a proper fix in the sequel.

Unused Sounds
Horn A honking horn in 2 different pitches, intended for Huitzil's one man band winpose. It wouldn't actually get used until Vampire Hunter 2, albeit at a higher pitch than either of these. Mooing Cow The sound of a cow mooing, intended for Bishamon's stage. Guitar Sample An instrument sample of a guitar exists, unused by any of the game's music.

Title
The game, as well as the series in general, is titled "Vampire" in Japan, and "Darkstalkers" everywhere else. The subtitle "The Night Warriors" applies to both versions of this first game, which often leads to confusion given that the international title of the sequel was also Night Warriors.

Character Names
Four characters have different names in Japan. According to developer interviews, the international names are actually the originals.

The kung fu werewolf is known as Gallon in Japan (a pun on a Japanese word meaning "hungry wolf"), Jon Talbain everywhere else.

The rocker zombie is called Zabel Zarock in Japan, and Lord Raptor everywhere else.

The curiously attractive fishman goes by Aulbath in Japan, Rikuo everywhere else.

And finally, the Mayan killer robot is called Phobos in Japan, and Huitzil everywhere else.

Winquotes
The Japanese version's winquote screen contains a decorative border graphic around the quote. The international version's quotes take up too much space to fit within this border, so it was removed.

Furthermore, the Japanese version contains a total of 18 winquotes for each character, as opposed to the international version's 4 per character.

Voices
In non-Japanese versions of the game, most Japanese voices were removed except for grunts and cannot be enabled by normal means, and there does not seem to be a way to reinstate the voices via the test menu.

Revision Differences
In the 940630 build, Rikuo's crouching hard punch cannot be blocked while crouching, which is extremely awkward given the attack's look and other properties. In subsequent builds it was made able to be blocked while either standing or crouching.