Revealing mistake: At the very end, a bat flying out of the mist toward the camera was intended to imply that Barnabas had taken bat form and could thus be around for a sequel. But through the haze, Barnabas can still be seen lying on the floor when the bat flies past. (01:36:25)
Revealing mistake: When Willie is hit in the back by the bolt from Jeff's crossbow, the outline of the packing material used to catch the arrow is visible under his coat. (01:32:00)
Revealing mistake: Barnabas lives by candlelight in Collinwood's "Old House," a 200-year-old mansion supposedly never wired for electricity. But just before Barnabas throws Willie down the stairs, there's a light switch visible on the wall behind them. (01:04:30)
Revealing mistake: Julia confirms that Barnabas is a vampire by sneaking a look at him in her compact mirror - which reflects his human companions, but not him. Unfortunately, the producers seem to have forgotten that vampires don't reflect when, near the end, we see the recently-staked vampire Roger Collins - in a mirror. Not even "dead" vampires ever appeared in mirrors in the TV series, so they shouldn't do so here, either. (01:27:15)
Revealing mistake: When the sheriff is handing out "silver bullets", in the wooden box holding the ammo you can see that none of the cartridges have primers. The cartridges will never fire without a primer. (01:21:20)
Continuity mistake: The wooden box (holding the "silver bullets" that the sheriff is handing out) has no markings on the side from a distance, but when the camera zooms in to see the ammo, you can see heavy black marks like someone crossed out a name and address, and you can also see a paper label partially torn off the box with writing blacked out. Then when the camera zooms back again, and the deputy picks up the box, the side of the wooden box is blank again. (01:21:20)