Dancers in her apartment(Spoilers)
I thought the dancers in her apartment was pretty creepy. The best manifestation of the Demon in the movie. IMO.
The reveal with Gemma was a poor imitation of the phone call scene in the first movie.
If she had answered the phone without looking and then realized she was talking to Gemma, that might have been better, though it might not work well with smart phones. Maybe if she had given Gemma a nick name in her phone, so that it wasn't so incredibly obvious?