Vampyr was made on the dawn of sound films and shot in three different languages; as a result, Dreyer used very little spoken dialogue and constructed an image-heavy, nearly silent movie. It plays like a very bad dream. Drawing loosely from J. Sheridan Fanu's ghost stories, Vampyr shows us a young man, Allan, who we are told is obsessed with the supernatural, coming to an inn where an old man enters his room on the first night to give him a letter to be opened on the event of his death. Wandering outside, he follows a series of beckoning shadows leading him to an even stranger castle where he spies through a window as the lord of the castle is murdered. Staying for a rest, he discovers that the younger daughter is slipping away to a terminal illness- it turns out she's being drained of her blood by a mysterious figure late at night. When Allan opens the package, it turns out to be a book on vampires.
This, then is a classic 19th century style tale of the eerie and uncanny. It's very effective partly because of how the uncanny events follow dream logic and also because Dreyer has an eye for surreal imagery. His silhouette camera tricks are very clever and quite often he frames things in ways that aren't quite right although it's not immediately apparent where they're wrong. It's a strange and slow-moving movie, even for the era, and might not be immediately accessible for modern viewers. Some viewers complain about falling asleep while watching the movie, which is appropriate because it's already like a dream. It feels as if anything can happen and Dreyer will break any rule of filmmaking. It's also a fascinating film because you can't just watch it and follow along from the start. Instead, you have to learn the logic of the world depicted based on what Dreyer is showing you or not showing you. For that reason, it's still a thrilling movie, both from a technical standpoint and because it's so creepy.