We can see a man pooping in front of everyone, very explicitly shown for few seconds.

Shows a young man's buttocks a couple of times (for comic effect)

Some other mild sexual references

Opening scene with a man axing someone violently to death. No blood and no direct shot of it though.

A woman punches a man in the stomach and he spits blood.

A lot of violence, both stylized and realistic.

In the opening scene there is one non-bloody severed leg and a woman gets shot with a shotgun.

A character gets his back broken (not shown) and foam comes out of his mouth.

The gang of antagonists is the "axe gang" carrying around axes as a weapon. Many-on-one axe attacks against an unarmed opponent are shown.

A man's head is hit so hard it twists around 360 degrees, killing him. (Shown but stylized.)

A man is decapitated and a cat is cut in half by "magic forces", both are only seen as shadows on a wall.

Mother and child get soaked in gas and a burning lighter is thrown at them. (It's caught by a character mid-air before it ignites them.)

A boy gets beaten up by a gang of boys and they urinate on his head.

There is a lot of violence but nothing overly graphic/gory. Some blood overall but mostly just from small cuts and bruises.

Blood is seen flowing from a door in an asylum. This is a direct reference to "The Shining", which Stephen Chow said to be one of his favourite movies.

A man is beaten and his head is punched so hard it goes into the floor.

1 use of piss 6 uses of ass 1 paired with hole 1 use of bitch 3 uses of hell 1 use of damn 2 uses of fuck

Some uses of ass and asshole

2 uses of fuck

The main character scrounges on the ground for cigarettes.

A protagonist character is a chain-smoker.

General alcohol consumption

Sing rescues a man from a dark and scary mental hospital.