Two things that niggle (spoilers)
Sorry for this, but:
1. Was Nanna raped at the flat or not? I thought early on it was said she was but the reading posts here suggests she was raped only in the basement at the house.
2. I don't understand Vagn's psychology. How does it make sense to rape and then murder a member of the family who is part of what you consider your own? If part of his motivation was her intention to leave, then how did her murder improve this fear/worry he had? I accept he killed Meyer, but that murder doesn't seem to fit him either.
The world forgetting, by the world forgotshare
Eternal sunshine of the spotless mind