Some of these pictures and descriptions may give away plot details that you might not want to know before watching the film.
This is proof that you can just throw a bunch of harmless pet store snakes on a floor, wrap a king snake or some corn snakes around someone's shirt covered with fake blood, and add some terrible computer-generated monster snakes and make a straight-to-video killer snake movie.
The backstory is not important - a submarine picks up some snake researchers who are studying some incredibly venomous nuclear mutant snakes and breeding them with rattlesnakes to create some enormous monster mutant snakes, and they both kinds onto the boat where a nosy sailor sets them free and they start killing everybody. Somebody thought they were also making a submarine movie so people are always saying things like "XO has the com" and other Navy jargon while they try to hide from the Chinese Navy which somehow snuck into the movie. They also added in Luke Perry and an attractive actress but fortunately they didn't create any real romantic possiblities to get in the way of the killer snakes.
They used a lot of nice-looking harmless pet snakes and buried them in horrible hissing and rattling sound effects: corn snakes, albino corn snakes, milk snakes, albino milk snakes, pythons, king snakes, and indigo snakes, pretending to be dangerous, but looking really cool if you're into designer snake breeds. With the widespread popularity of pet snakes these days, I would assume that most of the audience knows they're harmless, but apparently not. I guess most people just see any snake and start screaming.
Along with the normal snakes, we see a gigantic monster snake on the island and two snakes brought on to the submarine, grow very large after they escape.