Croc horror. Based on a true story in the sense that the crocodile actually exists (footage on the web isn't hard to find), but that's about it really. The size of the thing is royally exaggerated and the characters are vintage horror fodder, so it's better to see this for what it truly is: a simple creature flick.
I don't mind me some giant animal horror once in a while, though these films rarely stick out. Primeval is pretty entertaining and once the crocodile makes its entrance it keeps the adrenaline flowing, but as a film it is quite flimsy and it doesn't really do enough to set itself apart from so many others in the genre.
The performances are mediocre, the intro is way too long and the war crime angle detracts rather than adds to the film. If you're looking for quality film making, Primeval is going to be a disappointment, but if you can settle for a fun horror with a giant croc mauling everything and everyone that crosses his path, this wasn't too bad.