This is not to say it's a good movie, by any stretch. But it could all too easily fall into a variety of traps - too much of one thing, for instance (the titular snakes in this case. I really just wanted to write 'titular snakes' there. Score.) But the action is varied, the pace break-neck, and there are a lot of good jump-scares, as well as some stuff that you see coming from a mile off...and it's still horrifying.
It was a darned enjoyable experience, a mediocre film, and a raging success as a pop-culture phenomenon. What's next? "Snakes on a Boat"? "More Snakes On A Plane"?