I do not understand most of the comments saying 'This is the best game ever'.
VAGUE SPOILERS BELOW !!!
The scenery, graphics & movie cut scenes are without a doubt incredible and definitley most memorable from any game i have ever played. However, the actual gameplay, mechanics and repetitive actions became so boring and tedious that i didnt really find it so much challenging but rather monotonous as there was also hardly any puzzles which are somewhat the essence of Uncharted i find, and then i was left feeling pretty flat from a storyline that tried to end emotionally rather then blowing my mind.
All in all, its okay. Definitley play the other games first but by the time you get to play this, you may be let down by the end as it doesnt hit that Uncharterd sweet spot that the other games bring.