Continuity mistake: When Cooper is trying to console Murph before he leaves, he explains that time will slow down for him. In the first shot of the wrist watches side by side, the watches read at slightly after 9:00. Then Cooper says when he returns they can compare and the watches are shown again. This time they read around 8:20.
Visible crew/equipment: When Cooper steps into his car, just before the flat tyre, the boom of a microphone is visible in the reflection of the rear window. Also, the top of head of the boom operator is seconds later and remains visible for quite some time. (00:04:57)
Continuity mistake: Cooper drops a coin onto the binary sequence in Murph's room. In the next shot, the coin has moved.
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.
Continuity mistake: Midway through the movie, Cooper is said to be 124 years old while in the new galaxy, and at that time his daughter was still a young girl. Later, when he is back in our solar system and waiting for time to find an opening back to his daughter, who is now in her midlife years, he is awakened at the colony off Saturn, and he's told to take it easy because he's 124 years old but his daughter is a very elderly dying woman. Estimating her age at 90, Cooper should have aged a bit more.
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