The straw in the orange juice glass disappears without explanation, and it doesn't appear to be on the floor or on the lunch tray.
The glass of orange juice is down by half even though Ellie (Savannah Liles) is never shown drinking any of it, nor is any reference made to her having taken a sip.
The chair that Fonda (Richard Neil) wedges into the door handle would do absolutely nothing to prevent someone from entering or exiting the room.
In the final scene, the chess board is set up incorrectly. (The lower right-hand square should be white, not black). Also, as an added error in continuity, the board switches to the correct set-up later in the same scene.
Psychologist sees the girl demonstrate telekinesis and is not only not amazed, he doesn't ask anyone about it.
Ellie has 'age spots' all over her face and body (probably to look more intimidating, and smart for her age), but these are usually only developed from excess exposure to sun bathing. Giving the impression Ellie has been locked up in the facility almost her whole life makes next to little sense she has developed these age spots clearly all over her body.