I don't know where the hate is coming from, this flick has a super original premise (like wtf?!) and is paced really well. Never a dull moment and lots of twists and jumps. The acting is really good, all the actors killed it. There was a small plot hole in the third act, but they made it work.
A young couple head out to the wilderness for a mini-holiday and are mildly inconvenienced when a family of siblings arrive to have their own camping trip, right beside them in the woods. They are not nice people, as it turns out. It's weird, it's campy, it's unpredictable. It's a great lark.
Some nice ironic nods to the Manson family, good use is made of space, the camera work and direction are great. I think people just hate low budget movies. Thing is ... budget doesn't show in this movie. I highly recommend!