I disagree with the opinions of many of the reviewers of this movie; it is better than their two-star rating would imply. Yes, there are weaknesses: background on the characters, particularly the character played by Gillian Anderson and the two most agressive attackers, was sorely lacking. The ability to travel miles through the forest on foot in mere seconds stretched credibility, and personality reversals seemed to occur frequently and with indistinct motivation. Was the daughter actually being molested by her father's associates, or was it merely a possibility? What's up with the abrupt ending? etc...etc...
Despite the shortcomings, many scenes and situations were quite engaging. Anderson's character radiated an intense sexuality and her casual seduction of the security system tech was quite credible. I doubt that the "relationship" would have lasted long without the brutal interlude on their way home from the party, but once forced together by their shared horror and injury, the increasing pathology of their relationship becomes riveting. The gender reversal is a nice touch: she becomes stronger, dominant, and more bent on revenge; he shies away from violence, weak, damaged, and literally impotent.
Eventually, this reversal is reversed, albeit without full justification in my opinion. Her desire for revenge is quickly sated, far short of what was originally planned, while his accelerates dramatically. Another paradox is presented by the rapist/father: he claims to have only raped the Anderson character to distract his cronies from raping his daughter, but he did so with a level of brutality that does not seem consistent with a "fatherly" figure. Then, this brutal rapist/concerned father suffers remorse that leads him to attempt suicide, which will leave his daughter at the mercy of the men from whom he originally sought to protect her. Illogical, but an interesting sequence of events.
Likewise, the abrupt ending. At first I was shocked and disappointed, then I realized that nothing more could have been said or done. Any subsequent plot or dialog would have diminished the power of what occurred.
The mere fact that I felt compelled to spend time analyzing the motivation for these plot and character twists supports my personal conviction that there are moments of high quality in this production. When a movie is entirely bad, there is absolutely no compulsion for analysis. I admit that flaws and contradictions exist in this production, but like a stew made from things of varying appeal...in my opinion, there is enough here to justify the meal.
One final note: I agree with one reviewer in questioning the origination of the idea voiced repeatedly in reviews that the rapist/attackers were "hunters". It is clearly stated in the movie that the three men were out drinking and returning home. Hunting was never mentioned.