Continuity mistake: When everyone is at the second plane, Munro opens a box which is completely in sunlight. In the next shot it's covered in shadow. (00:34:00)
Continuity mistake: When Homolka stands by the plane, while Munro talks to him, Homolka's arm moves from being in view, to suddenly hidden behind the door. (00:34:45)
Continuity mistake: When the first missile hits the plane, Richard holds onto and comforts Amy twice between shots, as the plane begins to rock violently. (00:36:40)
Visible crew/equipment: When the first missile is shot at the plane, as the plane rocks, in one shot you can see a tape mark at Dr. Elliot's feet. (00:36:40)
Continuity mistake: When the plane is hit by missiles, Munro gives Amy a drugged banana to sedate her. Between shots the length of the banana changes. (00:36:50)
Revealing mistake: When everyone jumps from the plane, all of the stunt doubles are easily seen - [Dr. Elliot's stunt double is ridiculously easy to spot!] (00:37:00)
Continuity mistake: Just before Homolka jumps out of the plane, he puts his right hand on the side of the door and his left hand is holding his bag. In the next shot the hands have reversed roles. (00:37:05)
Revealing mistake: In the shot of a cargo box falling from the plane, a shadow from the plane is cast on the trees below, but the cargo box doesn't cast one. (00:38:20)
Continuity mistake: When Munro talks to Homolka at the campsite, about Dr. Ross, Homolka's cigarette jumps from his mouth to his hand between shots. (00:43:05)
Continuity mistake: When Dr. Ross is transmitting to Houston, she is holding her headset, but on the video screen in Houston, she isn't holding it anymore. (00:45:00)
Continuity mistake: When the two Ghost Tribals step out from the bush, the amount of white makeup all over them signifcantly increases between shots. (00:49:10)
Continuity mistake: When Dr. Elliot is faced with the Silverback gorilla, the size of the sweat stain around his collar and shirt changes throughout the scene. (01:02:30)
Revealing mistake: Richard takes a photo of a Silverback Gorilla in the forest, however the shutter is clearly closed as he supposedly takes the photo. (01:03:25)
Continuity mistake: As the group enters Zinj, a black man leads. As he walks through a cave, he is holding nothing. In the next shot he has a machete and gun. (01:05:50)
Visible crew/equipment: As the team walks through the ruins, a flock of birds bursts out of a bush. You can see a persons arm shooing them out. (01:19:40)
Revealing mistake: When the group is in the mines and there is a cave in, one of the porters is hit on the back by a (fake) rock, which bounces off. (01:21:05)
Continuity mistake: After the diamond mines of Zinj are found, Homolka gathers up the diamonds. When he asks Kelly to help, his hands change positions between shots. (01:26:54)
Continuity mistake: When the lava erupts out of the mine, it hits some gorillas. In the next shot, the lava covers the same stretch and hits the same gorillas. (01:27:55)
Continuity mistake: Nearer the end, sometime during the catastrophe in the mines, Dr. Elliot gains a large bruise on his forehead. This has later completely vanished.
Continuity mistake: Near the beginning the huge headquarters for the corporation that Dr. Ross works for is shown located in Houston. In shots you can see mountains, but the problem is that there aren't any mountains in Houston.
Answer: Seconds after he drops dead, an ape comes from where he'd been running from and throws a human brain at the living humans. This is Richard's brain, torn from his head. In the context of the film and employing a (fair) bit of suspension of disbelief, he must have had enough brain stem (where reflexes are governed) left to run and scream a bit before dropping dead. In reality, of course, this is an extremely unlikely if not impossible scenario, invented by the screenwriter for the purposes of a gruesome death. Perhaps inspired by stories like Mike the Headless Chicken, an animal which survived for months after having most of its head/brain chopped off.
That wasn't a brain that the gorilla threw; it was the head of one of the two porters with whom Richard remained outside the cave.
Phaneron ★