Credit for David Twohy. His script gives us interesting characters, thrills, and mystery that actually works. It works on a level that carries right through the revelation and on through to the final moments. There is a hint of depth that I did not expect. I will not give it away, but it does lead to an interesting decision in those closing moments. Then there is the direction — the pace is kept nice and even, involving, while also providing time for the possibilities to dawn on the viewer. I never felt rushed as the story fell into place.
On top of the solid writing and direction, the acting is also rather effective. It was nice seeing Steve Zahn in a role other than the comedic buddy. He handles himself well here. Milla Jovovich does a fine job as well; she is not a great actress, but always turns in decent work. The supporting cast is also solid, with Timothy Olyphant possibly being the most entertaining of the bunch.
Bottom line. This is not a great film, and I suspect many will not like it, but for my money it is finely crafted thriller with interesting twists and characters. It pays off in fine fashion, and is just a very solid experience. Set your expectations aside and enjoy the ride.