The film critic in question may be Bill Warren, author of Keep Watching the Skies!, the definitive survey of science fiction films of the 50s. He mentions the Medveds several times in that book, and never has a good word to say about them.
He does take them to task for lambasting films without seeing them, although that’s one of his minor complaints (which is why I say it might be him you’re thinking of). His main problem with them seems to stem from his attitude toward film. As far as I can make out, Warren feels that any film, no matter how badly it turned out, is the result of somebody’s hard work and creative effort. To approach a movie with the deliberate intention of mocking it, he seems to feel, is petty and mean-spirited.
While I take his point to some extent (and there may be a Great Debate lurking in this topic somewhere), Warren’s hatred of the Medveds seems to be way over the top. He calls them, among other things, “reprehensible,” “repulsively arrogant,” and “smug, merciless, and belittling.” Not their books, the men themselves.
Warren also seems like something of a hypocrite, since he is perfectly willing to make fun of some of the weaker movies that he’s surveying. His review of Cat Women of the Moon, for example, is quite entertaining. On the whole, I enjoy Warren’s writing. But the whiff of open hostility toward the Medveds makes some of his chapters a bit off-putting. On the other hand, some of Michael Medved’s recent screeds about morality in film are also off-putting to me. So basically, I guess I’m quite put off.
Back on topic, I too have always heard that the fake film is Dog of Norway.