The blonde girl having sex with Niki is shown wearing dark stockings. As the scene meets an awkward turn however, the blonde's legs are bare and then her stockings reappear in the next shots (Uncut version).
While the demon has the nurse in his possession he soon shoves both her hands into the wall of the hospital room they are in. This is practically impossible as the wall was lined with thick tile resting over an even thicker amount of drywall, meaning that her hands would not have penetrate the wall in the slightest.
The girls tormenting Niki were apparently hiding out in the school's gym equipment room, as in on school grounds. All seven of the girls are horribly and inhumanly mutilated in that very room (one of which was reduced to a skeleton), but the next day school is still open and the students make no reference to the event.
The goof item below may give away important plot points.
As chaos spills into Osaka, a purple demon is shown snatching a young brunette off the street and flying off with her. They are quickly shown flying over a stopped bus, but the upper torso of the girl (who is hanging upside down) passes safely through the bus.