I have only played the opening segment. I plan to start playing this soon as I greatly enjoyed Metro 2033.

As for a comparison to other FPS games? It is not bad at all. The gun play and other things are not as crisp as say Battlefield or COD but those games are built with a different purpose in mind. In Metro the emphasis avoiding combat and using as much stealth as possible.

While I am looking forward to Last Light, I wonder if the narrative can keep up with 2033. While 2033 was based on the book of the same name, Last Light is an original story. The author helped write this game so he was at least involved. I had even heard that he may adapt this story into another novel, Metro 2035.