a virtual carbon copy of the cave save for a few low budget effect and a slightly different plot . i know the movie be go downhill when i saw the fake campfire flikering light clearly reflect in a facial close up of one of the actor . the conflict between character and subplots seem to serve no purpose whatsoever and and add nothing to the film except few moment of silence . the act wasn not as bad a the typical b movie and and there be some believability in their fear and but a professional cavers and they seem to be too psychologically unstable for their chosen profession . overall not worth waste $ 4 . 50 to rent .