Awesome Music: The entire score by Björn Isfält. The usage of an organ as the main instrument elevates the score even further, given how organs are often played at funerals and the bulk of the movie takes place in the afterlife.
Thorn Rose Valley's liberation song. You don't even need to speak the language, the instrumental part playing at the end as the brothers ride home gives this troper chills every time.
Memetic Mutation: "All makt åt Tengil, vår befriare! / All power to Tengil, our liberator"
With the obvious counter "Död åt Tengil!/Death to Tengil!"
Narm Charm: The movie. It's very much a product of the seventies and has its corny moments but that's really part of the charm. And even with all that it's still an incredibly gripping movie.
Nightmare Fuel: Katla in the movies may seem silly both by modern standards, yet countless children have had nightmares because of her.
Special Effect Failure: The matte paintings are not exactly discreet. Also Katla, who looks like she was made from paper-mache.