Haneke is a challenging auteur. He method of protesting screen violence is by counterintuitively filling the screen with grotesque carnage (see Funny Games and its remake, and Benny's Video).
Here, thankfully, the violence is mainly psychic and emotional, as the characters seek meaning and connection in a world that seems cruel and indifferent. The first part of the two halves is engaging and generally skilfully executed, although it's hard to sympathise with the vandalism and selfishness of the teenage protagonists.
Part two picks up the story twenty years later and is a disappointment, striking me as a second-rate Bergman pastiche. As in Bergman, a clergyman is confronted with a lost soul seeking meaning and is unable to help. The characters deliver gloomy commentaries on the hollowness of human existence, and for the most part treat each other badly. I think we've seen all this before.
It's all like an anticipated football match in which the first half builds interest and excitement, all of which dissipates in a listless and meandering second half.