Near the end of the ritual, the heart monitor of one character goes into a flat-line (asystole), the character of Ann, who is a nurse, uses a defibrillator on that person. No medical professional would ever do that, administering a shock to asystole is useless.
At 24 minutes, when Angela is reading the poem JABBERWOCKY, the last line is misquoted. Instead of the correct word galumphing, Angela said galloping.
The demon in this movie, according to the credits, is Lamashtu, therefore, when it sees Chris McNeil, the "We've met before" quote is factually wrong since Chris met Pazuzu instead.