Someone has Vietnam-era war experience and PTSD related to it, exaggerated to an extreme degree by the eldritch phenomenon. Might be disturbing to people that are put off by that specific form of PTSD, though I doubt many people from that era would play this game. There is also PTSD revolving around survivor's guilt, being a bad person, and intrusive thoughts that can occur if the protagonist looks in the mirror.
You must abduct a mutated infant at some point, basically against your will. You're encouraged to kill it but can avoid this outcome if you try hard enough.
Flesh warps, plant matter warps, physical space and perception warp; the eldritch phenomenon in this game completely warps reality in a disturbing way.
Not really, people are either entirely reasonable to be horrified at their bodies because they're mutated, or it doesn't come up. There don't seem to be openly trans characters, so no gender dysphoria.
Body horror is often accompanied by abject horror from a person at their own appearance, sometimes with a detailed inner monologue of how horrifying they find their own body.
Not really, but there are "landmines" that have numerous human fingers in an arrangement that resemble spiders. There are also mutated silverfish, cockroaches, etc
There are humans mutated to resemble animals (or animals merged with humans?) that you must fight. Retreating instead of fighting them is possible. There is currently one situation that requires you to doom an animal to a horrible fate in order to reach the good ending.
(SPOILERS SPOILERS SPOILERS) The worst offender is a parasite entering someone's pupil and them trying to pull it out, all rendered in pixel art. Don't complete the dripping pipe quest if this is a trigger for you.
The game generally isn't reliant on jumpscares but there are some. Towards the beginning of the game, an eye suddenly appears on a TV and loud audio plays.