When Alice goes to the bathroom and gets up from the toilet to investigate the reason the curtain is moving, when she stands up she takes a deep breath through her nose but it sounds as if coming from her mouth.
When the flashback of Sarah's death is shown, Chucky's face has stitches where as the stitches are revealed later on when barb removes his plastic skin half way through the movie, not when he killed Sarah.
When Charles first meets Sarah, Daniel and Barbie the scene apparently takes place in summer as the weather is pleasant, everyone is in summer clothing and having a barbecue. Sarah is also heavily pregnant but a few scenes later the the film is set in winter and Sarah is still heavily pregnant. This would be impossible as a woman would not be pregnant at this late stage for more than 6 to 5 months.
In the black and white scene where it shows the past dinner party with Charles in the back ground. It shows a close up of Charles with Ray Bans on. There is a P (Polarised) on the Ray Bans which have only come out recently, post 2010. Nica was even born.
During the dinner scene it is implied Alice is the one who is eating the rat poisoned chili but Father Frank seems to be the one who is affected not Alice and Chucky was only seen putting rat poison in one bowl not two.
When Nica goes to investigate the screams in the first part of the movie as she opens and closes the door she appears to be moving in a way that implies she is standing and not sitting in the wheelchair.