As Dr. Carl is kidnapping Maggie and bringing her to his cave for the first time, we see a long shot of the mouth of the cave - look close and you can see the rubber raft that Maggie will row there later in the film, tied up next to Dr. Carl's reed boat. At this point the rubber boat should be back at camp, with the crew.
On landing in the crater, Maggie stands before a threatening carnivorous plant. Later in the film, after Maggie's clothing has been torn and her blouse has become sleeveless, she and Hal flee a T-Rex. She again nears the plant, but her clothing is complete and spotless, just as in the earlier shot.
Cdr. Roberts sends Steve and Maggie back to the helicopter when they are faced with the T-Rex for the first time. In the next shot with the T-Rex in the foreground, one can see Steve and Maggie hurrying off. However, it is at an unnaturally fast speed, showing that the film has been sped up at this point.
When the tarsier mammal is captured by the plant, the wires controlling the plant's tentacles are clearly visible.
The film is set in Antarctica, yet at the end of the film, when the occupants of the helicopter are rescued by the naval ship, it is clear that they are nowhere near ice-choked Antarctic waters. They should have been frozen solid in their threadbare attire once thrown into the water.