I'll try talking about this without giving anything away. So, having played the game nonstop for a couple of days (almost nonstop), I must say, the storyline sucks you right in. Again, Naughty Dog has you exploring multiple abandoned cities, cemeteries, caves, and even islands.
Although people complain that the puzzles/games aren't as difficult as previous Uncharted games, it is evident that Naughty Dog was concentrating more on storyline than they did on gameplay. Don't get me wrong, the gameplay was awesome; however, the storyline was phenomenal. If you're an Uncharted fan, like myself, you'll want to beat this game more than once. It was a perfect ending to an amazing tetralogy.