Father Philip actually punches his way into Pazuzu!Regan's chest and crushes her heart.
The Exorcist III
The Dream sequence; it has a very eerie, tranquil while sounding off key feel to it at first and then gets frantic and more overtly horrifying right before Kinderman wakes up.
Nurse Keating's death, one of the best Jump Scaresever.
In one scene, a statue transforms somehow with lighting into a Monster Clown with a dagger.
The Gemini Killer knows how to Hannibal Lecture better than the Trope Namer. Listen to how he's able to cut someone's head off without a single drop of blood being spilled. His description is worse than seeing it.
The part where he randomly starts singing in a high falsetto voice, and then abruptly stops. Both him and Kinderman act like nothing happened.
The exorcism scene; it may only be there due to Executive Meddling, but at least the crew had the decency to make it downright unsettling.
particularly horrifying is when a statue of Jesus being crucified is desecrated to mock the murder of Thomas, a young boy.
That wasn't a part of the added scene. You'll notice Father Morning is nowhere to be seen.