A house is set on fire and we see the burnt body of a young girl being carried away. Though the scene is dark and it's not easy to see.
A girl is stabbed directly into the eye with a nail, and we see closeups of the aftermath. The same girl is then beaten to death with a pole, the stabbed eye flying out and her face horribly disfigured. Easily the most brutal scene in the movie.
A girl cuts off a girl's finger with a knife. Not much blood, but we do see bone and muscle. Another girl's ankle is slashed with the same knife, and breaks.
In general, there is plenty of violence involving melee weapons. A boy is stabbed in the abdomen and his cheek is slashed. His whole face and body bleeds as he leaves a trail of blood trying to escape from his attacker. Though the attacker spares him from further attacks, he slowly dies off-screen from blood loss.
A man is kicked downstairs by a student who wore pins attached to his shoes. Later we see the wounds on his back, though not very bloody.
A boy's nose is crushed by pliers, before being shot in the head with an arrow. Very bloody scene, but also pretty funny.
A boy's stomach is sliced open and we see his guts hanging out.
A woman is liquefied by a snowthrower after tripping into its path. The snow that was shot out from the machine's discharge chute turns into blood and lasts for several seconds.
A girl bites her own tongue hard enough that blood leaks out of her mouth and stains her teeth.
A woman was accidentally set on fire and quickly engulfed in flames. Not bloody at all, in fact, the mediocre CGI would make it pretty comical if it weren't for the context of this scene.