Stripped of all it's dumb story line and viewed just for the underwater cave photography, this is a beautiful movie. The characters are weak, blah blah blah. But man, those are real caves (except for the chambers with the fire and the ice and the blah blah blah). It is unfortunate that the underwater photography has to be couched in such silly trappings. I would gladly watch endless hours of the explorations.
That has everything to do with Wes Skiles who handled the underwater camera. His work here is completely amazing. If you want a good claustrophobic cave story, of course watch The Descent. It is a far better movie in nearly every way. But if you love caves, you have to check this out.