Film Beaten over the head by boredom.
I actually watched the film twice. Both times, it was the Mystery Science Theater 3000 version. I decided to watch it out of Bile Fascination (thanks, Tv Tropes!). That being said, the movie is just bad.
First of all, what was the mission in which the supposedly deceased astronaut had done? Secondly, why was it so dull? Thirdly, what the heck was up with the ending? The movie raises more questions than answers, and the butt pull treachery of images didn't help matters, either.
I understand that the original producer ran out of resources, and there had to be new management. But for the love of the heavens above, why didn't he review what happened in the first part and go from there? At that time, my brain was nulled with boredom.
The finale was a long "Get on with it!" with many Leave The Camera Running moments. At that time, I was impatient, even though I knew that I wasn't going to be satisfied either way. Once that very treachery of images (there was no freaking monster) came, I was angry. It reminded me of North, only the latter was All Just A Dream.
Overall? Even if you're the least bit curious and found it via the So Bad It's Horrible page, don't watch it. Even the guys' riffing did not change the fact that it was a boring stinkburger (though I'll give them props for trying, though).
Film Not Even Entertainingly Bad
I watched this movie on an episode of Mystery Science Theater 3000 and man, is it one of the worst movies I've ever seen. Even worse than Manos The Hands Of Fate—while this movie has some technical knowledge of filmmaking behind it, it is so utterly devoid of charm, wit, action, or anything to the point that it's not even amusingly bad. The "monster" (a balding man in bumpy makeup) appears in all of three scenes. The movie is full of long, dull stretches in which nothing happens. In the end, there's not even a climax—just a long, boring build-up followed by the "monster" simply not appearing, after which the narrator informs us that the monster never really existed! Then why show us scenes of it killing people, and why was the army mobilized to fight it?!
Watching it on MST3K, Joel and the bots were the only thing keeping me from falling asleep, and even their riffing couldn't make it worthwhile. The sketches were funny, but the movie is so mind-numbingly awful that my brain hardly registered them.
Tl;dr? It sucks. Don't watch it.