It does keep you guessing right up until the end, because the end is a complete surprise you didn't see coming. There are some things that bothered me about the movie. The acting was a little forced at times, kind of like a bad TV movie. There wasn't enough depth to the characters, or the villain. And why didn't the three girls fight harder, I saw opportunities early on they could have exploited. Why did he do what he did? The Movie alludes to it but doesn't really say. The Hooks in the concrete basement floor the girls were chained to were obviously there for a long time. Had he been abducting women for a long time? Or was it something to do with the villain's mother?
Later in the movie Callie finds two little green toy soldiers that boys play with hidden in a crack next to her Chain hook in the concrete? Was the villain chained there as a kid, perhaps by his mother because he was "bad"? The upstairs of the house has an old feel to it...the furniture, the decorations. It almost looks like he's living in his mother's house, but you never see the mother. It did leave me with those questions, I felt like it could have been better with a little more back story and depth. But it wasn't all lacking, the plot and the girls kept me intrigued. Wanting to know more and see where it all ended up. And the end is a complete surprise, good one there!
From what I could find out this is a very young Indie film outfit with this being their first Major full length feature movie. Given all that, I'd say it was pretty good. In fact I'd say they would be ones to watch in the near future as they hone their craft and produce better and better movies.
So, yes, it's worth a watch.