The ending? (spoilers)
I have read several comments about people’s take on the ending and most people seem to have missed the point entirely. The very ending where Kate Mara is at the table and she looks at her hands and does that motion is identical to when Morgan did the motion earlier on in the film.
It signifies that Morgan’s mind and soul got transferred into Kate Mara. Since we last saw Morgan being drowned by Kate Morgan in the lake, I believed this was obvious but apparently people didn’t understand this.