This is nothing other than a Cannibal Holocaust ripoff (which I would recommend over this movie any day).
On it's own merits, the movie just about works, without ever coming close to shining. In the aforementioned Cannibal Holocaust (CH), you get something of a social commentary, which this one never delivers - moreover, CH had decidedly evil/perverse 'protagonists'; this movie's main characters varies from the very annoying (i.e. the stupid couple) to the slightly annoying (the vanilla couple). As such, it's difficult to sympathize with the characters, or at least find them interesting as one might watching CH.
There's the obligatory gore, the not-so-surprising ending, and just enough suspense to bother finish the popcorn. Quite run-of-the-mill slash.