I don’t know what i expected in all honesty. it was shot well and the tension gives you that feeling of being constantly pursued but at some point it does get comical. particularly the last sequence. all in all it’s a great laugh.
On the plus side, as is so often the case it is a nice idea, I love the idea of those cave sharks, blind, relying on sound, great, only they looked a little like Jaws III at times, and were a little on the dim side. The characters were such, that you didn’t care if they got eaten or not, and apart from the quite brilliant scene used in the trailer (you can see why) it didn’t really deliver many scares.