This seems to be trying to set itself up as a horror film - gas masked killer, 'teens' in peril, etc - but, in reality, that's not what it's about at all. When you finally realise what's happening, it makes you feel a little grubby and the good performance by Lakin doesn't help with that, because the actress really seems to suffer.
Once you get to the plot twist, though, the whole thing falls apart because there's absolutely no reason for the lead character to have taken his friends there, no reason for them to have been killed and no reason for the build-up.
A film of two personalities - Wolf-Creek-wannabe and incest-movie-of-the-week - neither works.