When Cole gets mouth-to-mouth, Sam's thong is showing. Then from a behind shot, you see no thong.
Multiple characters make numerous references to traveling "up river" despite the fact they are clearly traveling down river. Even after going over a waterfall they are all still in agreement they were traveling "up river."
If they had been traveling "up river" they would have gone up the waterfall which of course is impossible to do in a boat.
If they had been traveling "up river" they would have gone up the waterfall which of course is impossible to do in a boat.
As the boat fell down the waterfall, the crew should have been falling head first not feet first.
When Sam asked Bill what does his tattoo mean, he replied "that means 'a new beginning'" and it is Korean. In fact it means 'my world' and it is Chinese.
The revolver jams after having fired 2 rounds. Unless a revolver is almost completely rusted, the very nature of the mechanical action means that a revolver can not jam.
The CGI on the titular snakes is very noticeable. The worst offender is Ben's death, in which the snake and Ben are clearly CGI characters.
In the Conference room meeting in the beginning, the scientists says the blood orchid lays dormant for 7 years, then blooms for 6 months. The slide on the screen behind him in his presentation says 7 years, then 6 weeks. Later in the movie, they also change to a 6 week bloom time.
They are heading up the river but get into a waterfall.
The 'stone spider' is actually a golden silk orb weaving spider, harmless to humans and not native to Southeast Asia
There are no anacondas in Borneo. Anacondas are only found in South America.
In the opening sequence, Borneo tribesmen are seen hunting a tiger. Tigers have been extinct on Borneo for 11,000 years. They exist on nearby Sumatra, but the tiger depicted was a Bengal tiger native to the Indian subcontinent.
Monkeys with prehensile tails and the anaconda itself are native to the Americas, not to the island of Borneo in the Indian Ocean, where the movie is set; parakeets (budgies) are native to Australia.
During the epilogue, after a long travelogue through the jungle, the survivors are perfectly clean and the female protagonists have their hair clean and perfectly coiffed...
After the boat sinks, a member of the crew says "Hard Drive's ruined". The device being held in his hand, dripping with water, is in fact an ASUS 52x CD-ROM drive. Clearly not a hard drive.