A group of six friends finds themselves looking into disappearances within a secluded cave system, completely oblivious to an ancient being that’s watching them from the shadows below. It seemed like it could be a really good British movie about a monster. The young people in the story feel real and are well-chosen for their roles, and John Rhys-Davies gives a truly remarkable performance—he makes a big impact on the film. I was really into the background of the story and how this group started looking into the cave network where the strange creature lives. The place is bleak, dark, and has a strong feeling to it; you can practically sense the dampness all around, and it’s clear they filmed in actual caves rather than building a set. The practical effects are really impressive when we first get hints of what this thing is capable of, and holding back on showing its full form until about halfway through works well. It reminded me a little bit of *Alien*, because each brief look reveals something new about the creature, and seeing it completely at the end is quite a sight. My only complaint is that the effects later in the movie lessen some of the earlier suspense surrounding the creature, but I did enjoy the film overall, and there are some entertaining deaths for those who like their horror with gore.

Source on TMDB