Twist was pretty obvious? *SPOILERS*
I mean, we see "good" Gina see "bad" Gina in the red SUV, and after the unseen confrontation we see her drive away in the SUV. That kept nagging me till it was revealed that there were mirrors of the same persons. Then it was obvious that it wasn't the same Gina we were watching.
Retarded movie by the way. Fantastically shot, but incredibly inane.