Jesus, I can't really critique you on this, it's simply beautiful (god, that's the wrong word, but it is, in a sort of deluded, twisted way) Write more soon!
Its good few things to work on. Okay this isn't gonna turn into them having sex every other chapter is it? Because I think that subtracts to the feel of the hills have eyes. Which leads me to my next point. When are we gonna see the mutants killing some people? I want to see some good old fashioned blood shed. One last thing make sure to keep to the feel of THHE, because some stories don't keep to the feel of what they are writing about. Example I'm reading a terminator fan fic and the two main characters have had more sex than they have had fights. I wouldn't suggest putting too much sex in here, every now and then fine but still some more killing would be cool. I'm guessing I'm just rambling on here. Good job and continue on.