sorry but the “R” rating doesn’t tell people that the shape of water has an awkward gross sex scene and that a cat gets decapitated so yeah its kinda necessary for that to be pointed out.
it’s meant for parents but why not take advantage of a good resource
IMBD’s parental guide is good too http://imdb.com/title/tt5580390/parentalguide this has everything listed in the post, so if you are seeing a rated R film I recommend looking there