At the beginning of the movie, the intruder fires 8 shots at the two women. Revolvers only hold a maximum of 6 rounds.
In the opening sequence, before the audience knows any character names, actor Murray Brown is seen murdering 2 naked women, actresses Marianne Morris and Anulka, in bed together. The real estate agent in the final sequence refers to this as having occurred 40 years before the present action of the film. but vampires cannot be killed by bullets, and Brown doesn't appear to have aged at all in that time.
Harriett complains the castle looks rundown and scary, but no windows are broken or walls cracked, and the grounds appear to be well-kept.