Continuity mistake: While this movie is so bad and full of mistakes, its barely worth finding them all, one stands out in the history of movie mistakes. One of the officers on board the ship, Lt. Lamont, is killed by the villain. A few scenes later she shows up on the bridge as an extra.Grumpy Scot
Revealing mistake: As Reg fights with one of the baddies with the chainsaws, as the baddie take a swing with the chainsaw he misses and cuts into the wooden door. You can clearly see that a vertical cut has already been made in the wood though, to help the chainsaw get in and cut. (01:17:55)Hamster
Other mistake: As the brown truck drives away in the scene after the man working in the newspaper office is "harpooned" by a Critter, if you look closely as the truck turns a corner you can see some Critters rolling after it. Well, after they roll past the truck in the bottom left of the screen you can see the Critters roll right smack into another parked car. Obviously the crew forgot to add a turning feature to their Critter balls (which were just some fur taped to a basket ball).
Continuity mistake: When Celeste explains to the Elders why Earth should be saved she says, "They have sneezes", but doesn't explain what they are. The Elders don't look like they recognize the term. Later, one of the Elders sneezes, and says, "We don't have sneezes here." Now how could he know that he just sneezed, if nobody explained it to him?
Revealing mistake: We know that the blob dissolves flesh and hair and that it can also burn wood (since fluid coming from the blob burns a small spot on the desk in the hospital) and that it can dissolve bullets, but despite this obvious acidic state, the blob doesn't dissolve plants, walls, glass, concrete, metal, nor sticks and twigs.
Visible crew/equipment: Near the end when Wilford and Don and Kitty are about to sneak into the Oceanic Center, they are scoping out the scene. As they turn the corner, the shot changes to a shot mounted on the hood looking right at Wilford. You can make out the top of the camera's shadow near the right windshield wiper. (01:30:45)manthabeat