There's one scene in particular after the first torch sequence where the main character confronts an abusive parent where it is actually on-screen. The rest of the time it is alluded to or heavily implied.
VERY MUCH YES, there's one early sequence where YOU burn to death and also a very upsetting sequence near the end where you watch as another character is burned alive.
I think the dark rot in your arm (all it does it make your arm black and spread to the rest of your body to kill you) is the only thing that arguably counts as mutilation. I often have issues with this kind of thing and I don't remember anything upsetting.
Many people have died from torture, mostly off screen (or we just see their dead bodies). The climactic scene before the final battle is the one place it is shown directly.
Only if you jump off cliffs (which is pretty easy to not do accidentally). There is also a glowing figure in the shape of a person who jumps off a bridge and dissolves in the air.
I would say not really, but a core theme of the game is the main character having many voices in her head, and in some way it's kind of like you are possessing her as you play the game. Other than that, no.
There's one disturbing scene (right after you get knocked off the bridge, if you want to prepare yourself) where the main character heats her sword in the fire and burns her face with it.
Many times throughout the main character (who you play as) extremely intense anxiety attacks, as well as constant psychosis and arguably schizophrenia and delusions
There's lots of instances of expressing a desire for death, or attempting to exchange one's life for something in return, or not caring whether you die, and there is one scene where the main character is clearly suicidal (and being talked down by someone), but I don't think anyone ever actually expresses an intention to kill themselves.
When you finally enter Helheim (near the end of the game, after the Sea of [spoiler]s) a lot of the next sequence through the next boss fight (the Beast) involves some flashing red lights as an enemy chases you, though it's nowhere near a full strobe.
It’s vague language and may not be ableist to some but the main character is referred to as cursed and the cause of plague, seemingly because she hears voices. There’s a warning the beginning of the game for triggers in regard to mental illness.
Many times when Dillion appears as a clearer vision, he is naked, we only see above his waist. Near the end we also see Hela's full body who is nude. No genitals are shown, it isn't sexual at all but you can see her breast.
One of the lore runes talks about an incestuous relationship. Many of these lore runes have disturbing topics as they are direct from Norse mythology, but are contained as just stories for Senua to think on.