Yes, I'm very surprised to be putting this in Good Movies without any reservation.
An international team of scientists discovers a spacecraft of ancient origin buried beneath the Antarctic ice. They also discover one of its inhabitants buried some distance away. They dig the creature out of the ice and bring it back to their base camp for study. Unfortunately, the thing isn't really dead ... and it's far worse than a mere big, toothy monster.
Taken on its own, this movie is startlingly good. For one thing, it's serious. There are no bros, ethnic stereotypes, man-children, pot jokes, self-aware post modernism, pop-culture references, or forced romantic subplots to be found anywhere. This movie plays itself completely straight and makes a good-faith attempt to be scary. It even succeeds at doing so a few times!
What most impressed me was how the movie didn't try to top, or even match, John Carpenter's 1982 masterpiece. It actually goes in a very different direction with the titular monster. In Carpenter's movie, the Thing was a skulking ambush-hunter that had a preference for weak and unprepared prey. In this movie, it actively hunts its prey and, when forced into the open, aggressively defends itself and even manages to turn the tables on its attackers. This actually plays fair by Carpenter's version. The monster(s) in that movie could have learned from this movie that the aggressive method doesn't work too well.
When this movie gets it right, it really gets it right. The Thing's forms are all unique but of a kind. You can tell, as you could in Carpenter's version, that it isn't a proper metamorph able to change into anything at any time, but is able to manipulate its body to form structures like huge claws and constricting tentacles when it needs to defend itself. The Thing is also smart, able to make great use of absorbed knowledge, such as when it tries to use the overhead extinguishers to save itself after being set on fire. A sequence of the Thing stalking a man through the base's kitchen is especially well-done. This movie also makes great use of a little detail that Carpenter never seems to have considered but that makes a whole lot of sense: the thing can't replicate inorganic tissue. When this movie's version of the blood test doesn't work, the characters pick out who is likely to be a Thing by checking for fillings.
There are some things the movie, as a prequel, gets wrong. For one thing, in the 1982 movie, we saw that the Norwegians uncovered the flying saucer with thermite charges. In this movie, the Thing manages to get back on the ship and melt the ice covering it with the ship's engines. Also, the way this movie presents some of the 1982 movie's classic scenes is ... off. For example, it presents the iconic image of a man committing suicide with a razor as a brief glimpse during the closing credits. That should have been a money shot, dang it. Those defects can be excused, though, and anyone who hasn't seen the 1982 movie wouldn't even notice.
Then there are a few things that are just plain wrong, period. The scientists discover that the original Thing isn't quite dead after all yet they never dispose of its body, nor the partially absorbed body of the man it was attacking when they "killed" it. Then again, it never does come back to life to cause problems so, whatever. One of the characters, moments after saying that anyone could be the Thing and that no one should be alone with anyone else, puts herself in a situation where she is alone with someone else. Everyone keeps splitting up, well after the point when even the least sensible people would have decided to stick together, even if that meant potentially being next to an alien monster in disguise. One of the characters brutally murders another at the end of the film. I believe the intention was that we shouldn't really know if the victim was a Thing or not (of if the murderer was a Thing, for that matter), but some numbnuts went and dubbed the Thing's death roar into the scene, ruining what should have been the most powerful moment of the entire film.
However, I believe there is enough right here to more than counterbalance the wrong. The Thing 2011 comes within an ace of being a worthy prequel to one of the best horror films of all time, and is a damn fine movie on its own merits.