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.
The Scrappy: Corporal "Donny Most." Thankfully he's only briefly on scene. Hopefully the mantis got him.
Special Effects Failure: Any number, but the one that really stands out is a weird inversion that worked too well, namely a ridiculously thick patch of fog which obscures what is supposed to be a camera focus on a giant mantis footprint.
Visual Effects of Awesome: The life-size model of the dead giant mantis itself in the tunnel, which looks pretty good for a movie from that era.