I said this in another thread, but the details in the gameplay are what impressed me the most about The Last of Us. For example, sometimes when Joel gets shot, his body reels back, often pushing him back from cover, which isn't really used in a lot of other shooters (at most the HUD just flashes red), giving the combat a bit more realism. When you use a med kit, you'll see the bandage on your arm as well (which I thought was a nice touch). When you shoot at enemies, the enemies will often slump according to where you hit them. Or when you pop out of cover during combat, in many other games you can easily take a shot and hide again, but in TLOU, enemies will actually try to shoot you immediately once you pop out of cover.
Ellie often helps you out as well, whether it's throwing an object at an enemy or stabbing an enemy from behind (similar to what she did in the reveal trailer). There are just so many details that I've probably forgotten that went into the gameplay that made it go beyond what was already a good combination of stealth, gunplay, and survival elements (i.e., limited ammo and supplies). Maybe it has to do with difficulty, because I first played the game on hard (and later on survivor), so I did have far fewer supplies to work with, as well as more difficulty in sneaking (resulting in more improvisation during encounters).







