When Deacon Frost has decoded the text, and is looking at the image of the chamber, and the positions the purebloods must stand in are being shown with a click for each one, there are 21 clicks, but only 12 purebloods are needed, plus one position at the centre for Deacon.
Shortly before Blade snatches the disoriented little girl out from in front of the approaching bus, you hear it shift up and the engine speed picking up for several seconds. IOW the driver is accelerating hard on the gas. Strange reaction when somebody appears in front of your vehicle.
When Blade first opens the freezer to get to Pearl, there is lettuce in the top shelf. When he reopens the freezer and starts down the stairs, the top shelf has a tray covered in foil on it and the lettuce is gone.
During the final fight, when Frost punches Blade across the room (after super-speeding up to him): In the close-up of Frost, he swings at Blade with his right fist, but when they switch to the wide shot, he connects with his left fist.
The blonde vampire (Mercury) is wearing her white coat when she leads the purebloods to the glyphs. When Deacon says, "bring the elevator up," she's not wearing the coat, but it reappears the next time we see her.
In the subway, Karen falls into the gap between the subway train and the walkway; the gap is wide enough for her to stand up and give Blade his sword. In all other shots, the gap between the train and the walkway is clearly three or four inches at most.
After the encounter with Pearl and while Blade is held down by a couple of vampires in the scripture room, a vampire takes his sword and gets his hand chopped off like Quinn did earlier in the movie. When the sword hits the ground, we can see the handle is covered completely in blood. After reacquiring the sword while escaping and making a break for the subway tunnel, we can see the sword on blade's back again and the handle is completely clean without a trace of blood on it.
Just prior to the climactic fight scene in the Temple, Blade dramatically leaps from a high platform to the bottom floor. While leaping, his vest is clearly open. Once he hits the ground, it is zipped up and even clasped.
The blood collection chamber is opened to get Blade out and is seen left open. A bit later when the lighting storm happens and the lighting is seen hitting it, it is closed. During the subsequent fight scenes it is open again.
In the subway, Mercury's dress changes from white to blue back to white again due to the ultraviolet lights that were used to light some of the SFX shots (lights that wouldn't normally exist in a subway tunnel).
During the subway tunnel fight, the subway train takes over 60 seconds to pass by Blade and Quinn. If the train is traveling at 30 mph, then the train would have to be a half-mile long, or 66 train cars at 40 feet per car. A standard subway train is 8 or 10 cars long.
About 40 minutes into the film there is a shot (speeded up) of the Moon rising. However as it rises it moves from right to left when it should be the other way round. Without using a computerised telescope to line up a camera to point exactly where the Moon will rise, the film-makers filmed the Moon setting and then reversed the footage. What they should have was to also flip the scene.
The vampires, especially the Pure Bloods speak Romanian, probably because their ancestors come from Transylvania, yet in the temple when one of the guards holds the female Pure Blood still for the ceremony she says "Skloni te ruke s mene" which means "Take your hands off me", but in Serbian, not Romanian.
Silver has a melting point of 962 degrees C. Some alloys melt a little lower, but in any case, these kinds of temperatures are not obtained using a small, open-top, thin-walled bench top melting pot. Blade uses regular equipment for normal lead projectiles (melting point 327.5 degrees C), which would not work with silver.
In the opening scene in the hospital, when Blades mother is in labor, as the doctor opens the door, his hand slips from the handle and he almost smashes his face into the trolley, but makes a smooth save and the mistake is often unnoticed.
When a single small drop of vampire blood on a microscope slide and one drop of EDTA solution are sufficient to blow up a microscope, the explosive force of a whole vampire full with about an ounce or two of EDTA should proportionally produce a far bigger explosion than shown, at least on the order of magnitude of a large hand grenade.
There are twelve pure-bloods needed to complete the ritual, but Mercury seemingly kills one of them before the ritual starts. However, careful viewing of their entry to the temple floor shows there to be thirteen pure-bloods in the group. Evidently they brought a spare.
EDTA (ethylenediaminetetracetate), the anticoagulant Blade
uses in the glass darts, is not blue. The powdered form is white and produces a clear, colorless solution. However it is possible they would have coloured it blue in order to make it distinguishable from other liquids such as Blade's serum to avoid any mix-ups.
The vampires do not seem concerned at any time about the damage caused to their original Bible, despite its importance historically and to their immediate plans. That's because it's the information and not the artifact that's important, and the information has all been stored on Frost's computer.
When Blade is born at the beginning of the movie, the doctors talk about a Caesarean section to get the child out. When his mother reaches out for her newborn child, her belly is still very round and there is no blood.
In the background of the vampire nightclub after Blade's small killing spree a man is visible in the background, covered in head to toe with blood, however his bright blue shorts don't have a speck on them, even though it rained from the roof a few moments beforehand.
Obvious stunt double for Deacon Frost in the final fight. In various scenes, his stunt double (Clayton Barber) can easily be recognized. He is skinnier, has different hair, no red eyes en less blood on his face.
The goof items below may give away important plot points.
Towards the end of the movie, when Blade is trying to retrieve his sword from a wall, a cast member can be seen clearly in the background, jumping up and down, apparently preparing to enter the ensuing fight scene.
When the lightning strikes the temple, you see it strike the assembled coffin/sarcophagus that Blade had been locked in, but this is after Karen has let him out. A little later you see that the halves are still apart.
During the party scene, where Frost kills Officer Krieger: Prior to Frost biting Krieger and throwing him in the pool, there are 6-7 rubber ducks floating in the water. In the very last shot (where Krieger is shown floating dead in the pool) all of the plastic toys are gone.
At the end of the film, during the time the flying skeletons exit the vampires' burning bodies, the same bodies are unburnt and visible in the wide-angle shots. This is particularly noticeable when it comes to the two female vampires.
When Blade and Karen walk to the night club. Blade tells Karen that you must use a stake, silver, sunlight, or garlic. Also that it must be in the head or heart. Yet when he fights in the temple he stabs his mother in the stomach with a bone and she turns to ash.
When Karen knows the reaction between vampire blood and EDTA is going to be 'energetic', and in fact so much so that she feels the need to advise Blade to 'take a step back' - for what conceivable reason does she demonstrate it under a microscope? Gratuitously blowing up expensive equipment does not appear a prudent move for an underground resistance movement.
At the end of the final showdown between Blade and Frost/La Magra, when all the vial darts have hit Frost and his body swells up from the effect of the EDTA, you can see his left foot (right side to the viewer) "slide" sideways along with the pulsating of his bloated body.