These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Special Effect Failure: Averted by The Thing's costume, which is actually pretty good considering the budget of the film (The fact that the company that did creatures on Babylon 5 made it too, helps). Played agonizingly straight everywhere else though, as most of the special effects come in the form of stock footage, cheap optical effects, and really terrible CGI.
One of Reed's stretching scenes clearly involves two gloves on the ends of sticks.
Suspiciously Similar Song: Eric and David Wurst's score is essentially slight alterations of many popular John Williams pieces.
They Just Didn't Care: Maybe some of the cast and crew cared about their product. Roger Corman, as usual, got the film done on time and under budget, and though it's rife with corner-cutting leading to multiple Special Effects Failures, the Thing costume was actually rather convincing and the film did have a story. In this case, it was their bosses, the executives of The Constantin Film Company, who just didn't care: they weren't planning on releasing the film anyway since it was just an Ash Can Copy to help them keep the movie rights until they could sell them to Fox for a hefty sum, so what did it matter what went into it?