I haven't tried it on normal, but I thought that the hard setting was fairly difficult.  I died countless times, and I always felt that I was low on blade parts to make shivs or explosives.  I just started replaying the game on survivor and the fact that you can't use Joel's hearing "radar" already ramps up the difficulty.

I am fairly sure you can use it, but it is just turned off by default

Listen mode seems to be a toggle in the options menu for hard and lower, but the listen mode toggle disappears from the game options menu when you are playing on survivor (as well as melee prompts).  Enemies also seem to detect you much easier on survivor (have to feather the analog to sneak when enemies are close, whereas on hard, I could often crawl faster near enemies without being detected).

Oh god that does sound difficult... I had planned a second playthrough on survivor, but now I'm not so sure I can cope

Haha, yes, there's definitely a noticeable difference in difficulty in my experience.  It's going to take me far more sittings (and retries) than I did with my initial playthrough, that's for certain.

It's not a fast game, but a very good game

12 hours in and I am amazed how it manages to shake things up. This is truly a great game, though I am still not placing it ahead of Uncharted 2, it might have crept ahead of the other 2 though (Jak makes things more complicated)

+ Great storytelling we all expect from ND.

+ Some of the best acting I've ever seen in a game.

+ Environments are bigger than Uncharted's (3-4x the size, multiple paths in many areas), exploration is encouraged (for loot mainly, though you may find a key that'll be used for a safe somewhere around the map for example).

+ You can stealthily take out enemies or go all guns, but you'll be punished for the latter (low ammo). Sometimes you can just sneak by. "Choice-based" combat is the term I've heard used for it, and is fitting. Stealth works better than in Uncharted, and you don't get multiple hordes of enemies like you sometimes do in Uncharted.

+ Survival/rpg elements like looting and crafting are well done and paired well with the bigger environments, but - aren't so in-depth.

+ Little notes and leaflets and stuff you may find really adds to the story, the personal anecdotes that collectively help tell you wtf happened are my favourites. 

+ Clickers are terrifying, not just because they're scary monsters, but because they whimper and cry when they don't see you which creeps me the fuck out, as does the clicking when they do see you... literally fuck that noise.

+ Enemies are smart. They'll flank you, they know when you're using guns or not and act accordingly, that kind of stuff. Maybe not as smart as initially thought, but still better than most games. 

+ Obviously, visuals are amazing. Somewhere inbetween Uncharted 2 and 3 so not the PS3's best, but I'm guessing that's due to the bigger and more complex environments. So a step down from UC3, but still a + because it's well justified and still looks damn good, best art direction ever for a post-apoc except for maybe enslaved.

+ Sound design is excellent. All sounds you emit vary very accurately depending on surface and sorroundings. The way bullets whiz, the sound of a dude being strangeled, the bashing of skulls etc. all make combat that much more intense. VA ofcourse is god-tier. Music is generally ambient, and it really adds to an already rich atmosphere. 

- Movement feels a little ice-skatey if you know what I mean.

- AI companions not as smart. They'll help you out a little by fighting if you get overrun or telling you where guys are, but they get in you way (albeit very occasionally) and the fact that enemies don't see them can break the immersion. I know this was done on purpose, but I wish they found a better solution. 

- Some aspects of the story are kind of cliched (protecting the cure).

- Relates to above: The opening sequence was well done, but felt a little derivative. I wasn't blown away and it certainly wasn't one of the best opening sequences ever like people are saying.

So basically, the game is fucking GOOD, and I can't wait to play the rest over today and this weekend. What did you all think? (plox no unmarked spoilers)