A boy gets his leg bitten off piranhas in a swimming pool, filling it with very mild blood. The leg is not seen and it's like a scene from Jaws. Its not graphic at all.
A man is seen with his neck severely broken from a car accident. There is some bloody leaking from his neck and splashed on his shirt.
A man is attacked off screen, his body parts are seen strung up later on, and his headless body is seen, as well as his decapitated head (out of focus). His guts are covered up by bushes
Somebody gets their hand caught in a mouse trap and is seen screaming afterwards.
A girl gets in a fight with three men in a cafe.
Reference to Russian roulette
Dismembered parts of bodies are seen stored in jars (not too realistic)
A man is stabbed by a sword fatally and then falls backwards off a structure, hitting the ground with a thud.
Several birds are hit by a moving vehicle and are shown laying in the road twitching.
Images of brief intestines and cut off limbs are shown for a couple minutes.
A woman's face and neck are slashed gruesomely by a monster, this scene is brief, although there's a few pretty deep wounds shown.
A girl gets shot in the shoulder with an arrow. She then proceeds to pull it out.
The pilot episode is probably the goriest and most violent in the first season, as it includes a few bloody scenes, and a fair amount of death and murder.