Space shuttle pilots Grant and Tanner discover a giant alien spacecraft between earth and moon. During an investigation, Grant finds a football-like thing and a corpse of a 14'000-year old astronaut! Back on Earth, in a NASA laboratory, the mentioned football-thing comes to life and combines itself with the corpse! The result can only be described as sort of a zombie-robot killing machine. It soon wreaks havoc on everything in his path, but Grant manages to destroy it. On moon, Grant and Tanner then discover the remainings of an ancient civilisation! Inside a giant palace, they find the female survivor of a war that took place there 14'000 years ago, and they have to fight against other zombie-robot creatures. They are not aware that they brought the final piece of technique (their landing capsule) to the moon that allows an army of robot-aliens (known as "Kaaliun") to finish their spacecraft in order to conquer the earth! They've been waiting for 14'000 years, and now Grant must find a way to stop them...
I really don't understand why everybody calls this a B-movie. Maybe it was not in theatres in the US, but it was in Europe. The special effects are great. Of course, they used models in several scenes, but it was good model work. The film has exactly the kind of wonderful and frightening (thanks to Joseph LoDuca's score) atmosphere that makes science-fiction movies great. And we have Walter Koenig and the incredible Bruce Campbell, what more could we ask for? Yes, the movie isn't perfect, but what movie is? Yes, it can't be taken seriously, like most other SF movies either, and yes, a higher budget would have added to the film's quality, but the budget can't have been that low either. This film is also NOT an "Alien" rip-off and NOT a "TERMINATOR" rip-off, nor a rip-off of any other movie. It's idea has absolutely nothing in common with the mentioned SF classics and is very original. Contrary, it has been ripped-off by John Bruno's "Virus" in 1999. If you really call yourself a fan of SF movies, you simply can't dislike "Moontrap".
