Revealing mistake: There is a scene which features a nighttime view of Carfax Abbey, Dracula's home. This movie was set in the late 1800's/early 1900's, but if you look closely at the left-hand portion of the screen, you will see the lights of an airplane as it flies in the skies above the castle.
Revealing mistake: In the final moments of the scene where Dracula has been confronted by Dr. Van Helsing and a cross, Dracula flees by transforming into a wolf and jumping through a window. Look closely as Dracula approaches the window and you can see the mask worn by the stuntman just before plunging through the glass.
Revealing mistake: [ORIGINAL RELEASE - NOT THE DIRECTORS' CUT] Van Helsing, surrounded by the men, prepares to "purify" his dead Mina after unearthing her now-'undead' corpse. As Seward and Harker question her actual state, Van Helsing holds up a small mirror for them, insisting Mina casts no reflection. When Jonathan holds down the mirror to cast a look, you can catch a glimpse of Mina's hair and some skin.