Continuity mistake: In the flashback to the death of the headless horseman, when the horseman's steed gets shot and falls to the ground, the blood and the wound are on the right side of the horse...later in the scene when the horse is seen again, the wound is on the left side of the horse.
Continuity mistake: We are told that the horseman's sword cauterises the wounds it makes. Earlier on in the film, however, the cuts cause squirts of blood to fly into the air, such as when the scarecrow is sprayed with blood.
Revealing mistake: When the Headless Horseman is about to kiss Catrina's stepmother, you can see his actual teeth behind the filed ones. Christopher Walken's teeth are blacked out and their outline is visible against his tongue during the closeup of his face.
Continuity mistake: When that boy lights the spinning lamp that casts shapes on everything, we can clearly see the shapes on the wall behind him, but they never shine on him or his mother.
Continuity mistake: During the sequence where the Ichabod and The Horseman are fighting on top of the carriage, it's quite obvious that the two horses Masbeth and Katrina are riding keep changing colour. Sometimes they are both dark brown but sometimes Katrina's is dark brown and Masbeth's is white.
Continuity mistake: When Ichabod and young Mazbeth are in the shop looking for information and they find the boy's father's will, Ichabod's hair changes from a neat bob to really messy and scruffy three or four times each time the shot moves away from him then back again.
Continuity mistake: When Catrina's father is being violently pulled out of the church window, the horseman drags him in to a fence where his head is stuck in the fence. If you look at the man whose head is caught at first, his head is not all the way sticking out of the fence. The next shot, it is.
Continuity mistake: When the little boy is playing with one those revolving lamps (that are supposed to cast shapes and such on the walls of a dark room), you can see that the light source for the lamp is a candle flame. Candles, as you know, aren't extremely bright, and they flicker. Yet, the images and shapes being cast on the wall behind the boy are extremely bright and never flicker once. They're also not much like the shapes cut in the lamp.
Audio problem: Near the end of the movie, when Ichabod gives the horseman his head back, in one shot, the horseman has his sword in one hand, and in the next shot he puts his head on with both hands; yet we do not hear any sound of him either dropping his sword or re-sheathing it.
Revealing mistake: When the whole town's in the church and Katrina's father gets the pole through his stomach, if you watch while he gets dragged through the graveyard, he hits a headstone and it moves back.
Continuity mistake: In about the middle of the film where Ichabod Crane is writing doing process of elimination. He writes "Baltus" in cursive. Watch the tail of the "s" on "Baltus." One or two shots after that the "s" on "Baltus" is clearly different than the one we watched him write. The "l" in Baltus changes too.
Continuity mistake: When Ichabod Crane and young Masbath are riding to the Tree of the Dead for the first time, watch the boy's horse carefully. The camera pans behind a tree and when it comes out from behind it, for a second you can only see Gunpowder's haunches (Gunpowder being the grey that Ichabod rides) and not the chesnut's. Very hard to spot if you are not watching carefully.
Continuity mistake: At the start of the movie where Ichabod is at the City of New York Municipal Watchhouse there is a medieval device to Ichabod's left, which is open and empty. In the following shot, there is a man standing inside with the doors closed around him.
Continuity mistake: In the shot where Baltus Van Tassel is speared through with the fence post at the church, you hear a pane of glass in the window break but you never see the post actually go through the window nor do you see the rope that is tied to it at all in the shot. The post simply "appears" coming out of his chest.
Continuity mistake: When the widow's body is on the operating table, in the wideshot Ichabod removes the first medical instrument from his bag and is placing it on the table. In the next close-up, as he removes his hands from the instrument we see that it is actually the second instrument he has put down, with the first one right beside it.
Continuity mistake: When Ichabod arrives at Jonathan Masbath's murder scene, he selects a small bottle full of green powder to begin his investigation. The amount in the bottle changes from half-full to full in between shots.