Plot hole: Through this film (and its predecessor) it is established that the creature imitates its victims perfectly, having all of their knowledge and memory. At the end, when the female lead tells the male lead she knew he was human because of his earring, he reaches for the wrong ear, confirming he is The Thing. Even if The Thing couldn't reproduce the earring, it would have known which ear it was supposed to be in.
Plot hole: Supposedly the thing landed/crashed and crawled out afterwards into the freezing arctic, where it froze solid. Well and good. Why did it leave the ship into the freezing environment it could not tolerate? As soon as it enters the ship it fires it up and starts to take off. So there was apparently nothing wrong with the ship requiring it to go outside in the first place.