Continuity mistake: When Kelly is on the boat with Hank and the soon to be headless deputy, her green vest (life-jacket) is fully unzipped. When we see her immediately after she's been knocked in the water, her jacket is zipped almost all the way up.
Visible crew/equipment: When the sheriff is listening to Betty White regarding how her husband dies and they begin descending down the stairs you can see the boom mic above the sheriff's head.
Continuity mistake: At the end of the movie, Bridget Fonda's character is trying to get away from the crocodile in the water, which she eventually does, but right after that scene she is on land, and her hair is dry.
Continuity mistake: In the opening scene at the beginning of the movie, the Sheriff and Fish & Game diver are going to tag beavers. There is a clear shot of the diver under water at the beaver dam with a white oxygen tank. Shortly after he is attacked, part of his suit surfaces in the water with a black/gray oxygen tank, not white.
Continuity mistake: When Betty White's character is about to feed the crocodile, the second shot shows the cow with a smaller blindfold than the first one.
Continuity mistake: After Kelly has finished talking on the mobile phone at the lake she puts the antenna down then in the shot immediately following puts it down again.
Continuity mistake: After Jack shoots the dart at the crocodile trapped in the helicopter, it is visible in the animal's jaw. After the attack by the second crocodile, the dart has gone. A moment later it is back again. (01:09:20)
Continuity mistake: The Crocodile changes size in between takes and shots. Example: In the scene where Hector is swimming with it, from a top view, it's head is small. When it goes to view from underwater, it's head is bigger than Hector.
Continuity mistake: During the scene where Hector finds himself with the 30 foot crocodile, he blows up a raft and leaps on board his helicopter and takes off to find that the crocodile has bitten down on one of the pontoons. The crocodile clearly bends the pontoon with its teeth. But when the helicopter finally goes airborne, the pontoon is fully intact, only the tarp covering is ripped.
Deliberate mistake: While Hector is in the water with the crocodile, he yells to the female officer to start the helicopter by turning the key. It takes a lot more than just the key to start a Bell Jet Ranger helicopter. Fuel shutoff valve, throttle, key, and the main rotor doesn't start rotating until the throttle on the collective stick is turned to a specific position.
Factual error: Grizzly bears are not present as far East as Maine and therefore would not have been anywhere near Lake Placid.
Visible crew/equipment: Near the end, when Kelly and Jack are in the boat heading out to the middle of the lake, the tip of the boom is visible just above and to the right of Jack's head.
Revealing mistake: During the opening sequence, when the fish and game officer is just about to be attacked while looking inside the nest, there's a clear reflection of his lower body as the camera moves closer from behind him. This reveals the diver is in some type of tank, otherwise, this could be a piece of equipment, like Plexiglas (or similar,) put in place within a real body of water for filming purposes.
Audio problem: During the open sequence, when the fish and game officer is dragged across the water during the attack, you can hear him screaming with a scuba regulator in his mouth. While it's possible to scream with a regulator in, it wouldn't sound like that.
