I wish I hadn't been aware there was some cat-directed violence before I watched the movie. I was a little tense waiting for it and, from the comments here, was expecting something really horrible. It turned out to be quite discreet, and, since it involved a fucked-up boy doing a fucked-up thing because of the fucked-up things that had been/were being done to him, there was nothing frivolous or exploitative about it.
Do we think poor eldest daughter asphyxiates in the end, by the way?