I may be a bit late to the Uncharted party, but I couldn't resist sharing this tip for those who may still be working towards their Platinum Trophy for Drake's Fortune.
Fans of the game may be familiar with the area known as the "blue room" or the "water room" near the end of Chapter 5. With little cover and flanking enemies, this room presents one of the most challenging firefights in the game. It's manageable on lower difficulties, only requiring a little luck for some on Hard, but it can be quite unforgiving on Crushing.
If this room if giving you trouble on any difficulty, here is a little cheat to help you get through it:
The trick is to get the enemies to spawn before you drop down into the room so you can simply pick them off from the entrance. To do this, walk up to the ledge at the entrance of the room, but don't drop down. Then turn around and head back down the tunnel you came from and climb back outside into the sunlight. Fire off a round from your gun, or the turret that is there, and you should hear the battle music kick up. That's your cue! The enemies are now in the water room. Head back to the entrance of this room and stay up on the ledge while you take them out. The two shotgun toting pirates that spawn last from the entrance you are standing in will run right past you as long as you don't shoot them before they drop into the room.
Click here for a video showing this technique (skip to 3:40 for the blue room).
Happy treasure hunting!