After reading. listening and watching content about this game the main and sometimes only thing I've learnt is that Dark Souls is hard but fair. That's all well and good but what else is good or bad about Dark souls? 
 
How is the sound design? 
 
Does the visual design fit the tone of the game? 
 
How beautiful are the graphics? (I've watched the quick look and it looks great) 
 
Are there any special features like developer interviews and making of featurettes in the game? 
 
Can you invert your controls or not? 
 
For those of you who have bought and played the game, what would  you tell a prospective buyer other than the game is brutal?

The only pertinent question that now needs to be asked, is whether Steve Jobs will turn into a phantom form and proceed to kill you if you don't buy his Apple products in-game???

WHAT??....

The graphics are awesome, and the environments are done very well to fit the tone of what the trailers were trying to show you, Death and destruction is everywhere. The sound is, you hear footsteps around corners as things chase you, you hear things die as they actually die (Everyone talks to you through telekinesis as no ones mouth ever opens unless their a monster. I dont know if the controls can be inverted as i forgot to look before i quit, but i dont see a reason as to why you would want them inverted as it works great as is. The developer stuff would be in the CE if anything at all but since it is a japanese game i doubt they would have one for us anyways. I would tell everyone to get this even if i know thy would hate it just because of how fun it is. I have died more times in these past 2 days then i have combined in my 200+ hours of demon's souls.

Though I haven't found the overall atmosphere to be as strong as Demon's Souls (yet anyways, or maybe it's because "I've already been through this before" with Demon's Souls) but it still has a great overall atmosphere and characters. 
 
Personally, the key for me is the combat. There is just something about it's "wait for your opening and take it" that is extremely satisfying to me. I also find fighting multiple enemies very satisfying purely based on how each attacker exponentially increases the difficulty of the situation, even if they're weak. 
 
The other thing I really enjoy (and this was never really explained to me before trying Demon's Souls for myself) is the risk/reward system the whole game revolves around. Do I push forward, gather a few more souls and risk dying, or should I head back now and level at the cost of respawning all the enemies? It's constantly on your mind and almost gives you that survival-horror type of tension. 

Yes, the controls can be inverted (at least their was a option for it in the menu, I can't guarantee that it actually does what it says :P) .

@Masha2932: Dark Souls is out tomorrow in the UK so I haven/t played it, but as a 'vet' of the first one I can safely say the 'hard but fair' thing, although has been repeated a lot by many people - there really is nothing else like it out there at the moment. It's a massive statement in the face of how friendly video games are at the moment. The graphics are quite unique, the sound design and music for the first game was fantastic, and the atmosphere like @ProfessorEss: mentioned had this unique-SUPER-depressing feel to it that just made everything more scarier.

For a prospective buyer, I can say these games really feel like a test of your skills. When you mess up in Demon's/Dark Souls, you mess up because YOU made a mistake, and it really feels like that. When you come up against a new and really powerful enemy, you genuinely feel afraid of what they might do to you if they catch you off guard - it keeps you on your toes. These games are just a really unique experience. It's definitely hard to describe.