Continuity mistake: When Cooper draws on the board and talks about landing on water, his drawing changes between shots. (01:04:25)
Continuity mistake: Cooper is saying goodbye to Murphy. Her necklace jumps in and out of her T-shirt throughout the scene. (00:38:25)
Continuity mistake: When Murphy pleads with Cooper to stay shortly before he leaves, as she shows him the message "STAY" on the notebook, in the first shot she looks down, but in the next one she looks at Cooper.
Continuity mistake: At the beginning of the movie when Cooper and the kids arrive to the lake after they took the control of the drone, Murph steps out of the truck and leaves the door open, but in the next shot the door is closed and it's sure that in the entire scene there's no sound of a car door getting closed.
Chosen answer: They do not still have gravity. Romilly is actually floating, but nothing is ever shown from behind his back, so the floating is gone unnoticed. In fact, during some shots of Romilly, you can see his feet floating behind him.
Casual Person