I saw this on MST3K, and it's one of my great favourites. The endless map sequence at the beginning is quite hilarious, but my weakness for this movie stems from the fact that almost the first third of it takes place in Canada's arctic, and my dad actually worked on the DEW Line while I was a kid. The stock footage of the building of the radar lines up in the Arctic was fun (stirring music and all), but I think that someone connected with making the movie must have either been on the DEW Line, or knew someone who had. There were so many odd little details I've never seen in another movie, even though 'The Deadly Mantis' is not original in its use of the military to fight off a giant invader. The giant "Check Your Antifreeze" sign prominently displayed at headquarters was one - who would think of a detail like that, unless they'd actually seen it somewhere? And the most bizarre thing was the guys dancing together at the little party on the base; when you think about it, it makes sense - no women up there, so if you want to dance, you'd have to have men dancing together, but it's just not something a writer would just dream up while writing a movie. Alas, my dad died before I saw this movie, so I couldn't ask him how authentic it was in its portrayal of life on the DEW Line, but I think of him every time I watch it, and I'm sure he would have laughed uproariously.
Review of The Deadly Mantis
