There's some kind of genetically mutated crocodile that escapes and begins killing people. A few people from the town it's attacking, along with a crocodile hunter guy, are trying to stop it.
I can think of at least three things that ended up being funny, but that, if real people were in a similar situation, probably would happen, such as the guy who acidentally pricks himself with a tranquiliser while being attacked, which is realisic considering he's panicking and his hand is in a box of tranquiliser darts.
And no, this movie isn't 'so bad its good' or anyything stupid like that, it's genuinely entertaining.
Thankfully, aside from the horribly overused 'get out of the water!' line, the movie avoids any clichés, unless you count a character who acts surprisingly like Steve Irwin, which I doubt counts as a cliché since Steve Irwin actually is a real guy, although it's strange that so many australian characters in monster movies act like him. I guess this is going to be the last time for a while though, because it's going to be something of a taboo for a long time.
While CGI creatures in monster movies have always had some amount of cuteness, from the Jurassic Park movies, where the 'cuteness' was accidental and a result of the CGI creatures being extremely stupid-looking, to more recent movies, where it seems to be intentional, the title creature is possibly the cutest CGI movie monster. That's why this is possibly the second horror movie I've seen in the last few years that I'm happy had a twist ending. I know a fifty-foot crocodile that swallows people who shouldn't be able to be cute, but it is. I guess this is another sign of how anime and tokusatsu have influenced western culture over the last decade or so.
Anyway, my overall rating for this movie is 8/10.