Haven´t seen any dog but no one mentioned that a rat´s tail is cut off, I haven´t seen the circumstances but you can anticipate nothing good, around 20:30, after the ¨mute¨ boy´s drawings.
The ending is overall happy. The last scene is of the family genuinely happy together sharing a meal. Many traumatic and sad things happened to them during the whole series, however.
The parents are narcotic addicts and/or alcoholics. There is minor physical abuse (similar to spanking), severe neglect abuse (living in squalor, no food, etc).
The children were neglected and abused by their parents (mainly neglect), but they both continue living with them once they are 18+ and they are shown as a happy family at the end.
A teen with MS is in a wheelchair. The actors do not use wheelchairs in real life. An adult has a facial deformity covered by a prosthetic from a gunshot wound. The actor does not.
Someone is killed off screen and his face is removed and stored in a vat in a lab. The head is seen in two scenes (when discovered initially, and when shown to expose the murderer).
A woman is beat by her boyfriend, including hitting, punching, pushing her down, choking her, trying to drown her in shallow water.
Spoilers, not major to plot: The woman gets away with minor injuries. The same man calls her demanding she come back, then comes to get her from her safe house with other truck driver men. Someone else threatens them and they all leave. The abuser is not seen again.
A blue wren is stepped on in the climax of the final episode. Wren is CGI, so while you see the boot crush it there is so not an overly realistic struggle and no graphic image of the wren is shown afterwards.
about 19:00-21:00 — A child makes another child hold a live rat that is wrapped tight in saran wrap, pulling it lengthwise so he can attempt to slice it in half with a sword(?). The rat survives & escapes, but it’s tail is cut off.
There is a laboratory scene with a dog and monkey that are whimpering. I had to look away so I didn’t see anything else. A bird is whimpering and is then killed by the villain.
S1E1 (trigger warning: child abuse, SA) A young boy is ordered to drop his pants at school. It’s for the administration of lashes, but to me this will always read as sexually abusive. The authority figure (principle, maybe?) is a little creepy too.
A teen's finger is cut off with a knife as part of torture. A leg washes up on the beach. Multiple characters work in a prosthetic factory, so fake arms, legs, etc are shown (they are older style and not very lifelike).
An agoraphobic adult has a panic attack when encouraged to leave the house. He is shown on the floor, paramedics arrive, he recovers quickly. He later gets over his agoraphobia.
13 and 15 year old crawl through a small mud tunnel under a house. The tunnel is large enough for them to crawl on hands and knees upright. At one end of the tunnel is a basement, at the other is an outhouse. The children are locked in there for a few hours by the stepdad. They eventually emerge covered in mud and feces.
In the last episode, two adults go underground into a long basement-like area with one trapdoor entrance/exit. It is not a very small area (they can stand up and walk around freely, it is probably 2000 sq ft), but that there is one exit is a bit claustrophobia-inducing.
The woman survives, but a woman is held underwater in a shallow bowl by her boyfriend who is trying to drown her.
In another scene, a car with children in it crashes into a lake. It does not seem like one child will survive, but everyone does.