Mercury

Continuity mistake: When they are all outside and MacReady has separated the three most likely suspects and orders that they be tied down and tested, he comments at that time that they are to be hit by a storm in six hours. Cut to the scene where Mac is dictating into his recorder and he comments that the storm has been hitting them hard for 48 hours. However it is the same night and at best, maybe only an hour has passed.

Mercury

Continuity mistake: When the dog, aka the The Thing, is led into the dog pen for the first time we see the floor is covered in a thick layer of straw for the dogs to sleep on. This is seen every time except when Childs uses the flame thrower. We get a wide shot of the pen as it's lit up in flame and the floor is now completely bare of any straw. There are also none of the recently deceased dogs that were lining the floor, being converted into Things. (00:31:05)

Mercury