Continuity mistake: When Andre puts Blade in the suitcase, Blade's knife is missing and there's nothing where his left hand should be.
Continuity mistake: When Frank and Carissa are having sex and Carissa notices the door is open, her hair moves from hanging over her shoulder to behind her shoulder. (00:49:15)
Continuity mistake: When Blade gets on the elevator in the beginning, pay attention to the legs of the woman in the elevator. When she gets on, she is wearing black stockings. When she gets off, she is wearing cream-colored stockings. The rest of her clothes that are visible are the same (same shoes, skirt, etc.), as is the wardrobe of the man who gets on and off with her, so it's meant to be the same woman. (There's also no indication that the elevator made any stops on the way up).
Continuity mistake: At the beginning of the movie, we see, from a POV shot, Blade running towards a road when the car carrying the two assassins pulls up in front of him and the two men get out. The shot then changes to an overhead view of the car. Blade should be visible in front of the car but isn't. (00:04:46)