At first I didn't understand but then I realised...
This movie has a 5.4 rating and at first I felt it was underrated but then I realised why. The story was really well written but the acting in general was flat and the cinematography just wasn't very good. All the scenes felt the same and blended together.
Usually you can have great actors but then a horrible movie due to a bad script or similar issues. But still with good acting at least.
Here it was the reverse, a great script and story but just bad acting from great actors. I guess it was just poorly directed is the only thing I can figure. A great director can get even bad actors to act extremely well. While a horrible director can make great actors act poorly.
That's my two cents though.