Some of these pictures and descriptions may give away plot details that you might not want to know before watching the film.
"What a horrible way to die!"
"They're waiting to slither you!"
Boy is this a bad film - lousy plot, terrible action, bad acting and unbelievable dialogue. It's hard to find much worse. The only thing good I can say is that most of the natural history information about rattlesnakes given is accurate, even if the behavior of the snakes was not - chasing people, biting multiple times, and even biting the tires of moving vehicles!
The plot revolves around a den of rattlesnakes getting contaminated by CT-3, an experimental nerve gas that was developed to cause behavior so violent that the enemy would destroy itself. The gas is being horded by a rogue Army colonel. None of that would explain why the snakes are spreading in a straight line for many miles and attacking people whenever they meet. Two young boys are viciously killed by rattlesnakes when they fall into a pit full of snakes. Snakes take over a house, coming through the pipes into a woman's bathtub, killing everyone in the house, and causing it to be burned to the ground, and more snake mayhem. The snakes used in scenes with people are not rattlesnakes, but they use plenty of them in other scenes, including cutting back to the same shot of a captive rattlesnake with only a couple of buttons on its tail (couldn't they at least have found a better looking one?) Many of the snakes looked like Western Diamond-backed Rattlesnakes, but a kitchen full of snakes appeared to be some kind of Western rattlesnakes. The harmless snakes were gopher snakes and others. According to the credits, snakes and advice were provided by Hermosa Reptiles and Ray Folsum.