When I first came across the description of this movie I thought it sounded something like "The Descent" - a movie I really enjoyed. I decided to watch it, thinking that it would be a poor copy of that movie. But it's not a copy. There are no monsters - just basically a love triangle between three people (two guys, one girl) who decide to explore some normally off-limits caves. With a diving element involved in this, I also thought it sounded a bit like "Sanctum" - which I also enjoyed. I suppose there are some loose similarities to both of those movies, but basically I was disappointed in this. It's a very short movie (under an hour and a half) - which might be the best thing about it, since you leave it behind at least knowing that you didn't waste too much of your time on it.
It's a Norwegian movie. I watched a version dubbed into English. That makes it somewhat difficult to offer an assessment of the cast - but none of them really stood out to me. It does manage to capture the claustrophobic environment of spelunking - but, then again, surely that isn't especially hard to capture. There really didn't seem to be a lot of chemistry between the three leads and the movie was neither especially tense (although there were a couple of moments) nor was it at all frightening. I'm not one who is big on long extended introductions to movies just for the purpose of establishing a backstory for the characters, but to be honest a little bit of that would have been helpful. As the movie goes on bits and pieces of this are revealed (so Charlotte, who's in a relationship with Adrian, used to be in a relationship with Viktor; and we find out that the three had apparently served together ion Afghanistan) but we don't really learn that much about them and by the time what we do learn begins to be revealed - well, to be honest I had kind of lost interest.
The movie's open-ended, suggesting the possibility of a sequel (which, in fact, is "promised" - or threatened?) in the closing captions. I won't be watching it. (4/10)