It's quite clever to put a shark movie in a dark cave. It does save a lot on the effect budget when you don't have to show the main antagonist with any degree of clarity. The characters are fun enough, even though they aren't very engaging, and they all get picked off one by one by a very angry fish just doing fish things. What I did like about this is that the fish isn't actually malicious or supernatural or vindictive, it just does fish things and that's pretty cool. For a cave movie this doesn't rate very high and as a shark movie, it doesn't rate much higher. It isn't a bad movie, but it isn't really all that special.