I'll place this film in the same category as Eden Lake (2008), Ils (2006), Martyrs (2008), Inside (2007), The Vanishing (1988) etc, etc.
This stuff seems more common in European cinema. American films tend to be more uplifting.
The last 30 minutes had my stomache in a knot. It's been a long time since a movie has done that to me and I watch a lot of horror movies. I thought this was a great movie.
This fits well with the movies you mentioned. Inside is one of my favourite horror movies, that was similarly unpleasant to watch as Speak No Evil.