Though it's a very well-made movie with strong characters and emotionally resonant situations, it can be very intense and frightening, especially considering that a 6-year-old boy is frequently in peril. There are nightmare sequences, knives, stabbing, and some blood and gore.
This movie explores the more disturbing and realistic side of the genre, I'd say it's more haunting than said movies for sure. It's psychological horror at its finest. It actually gets under your skin, and when a movie can do that, it has done its job.
It's very scary, but not that graphic; occasionally a character will get shot or harmed by another, but most of the violence in The Terror comes from nature: dying from a great fall, for example, or being frozen alive.