The original Dark Souls is a pinnacle of game design, honestly. The structure and game mechanics, and how the game world is laid out without fast travel, everything linking up, which really makes you think before using bonfires and your items. It becomes almost a survival game at regular intervals.
Though I disagree with people saying it's hard, I don't think it's actually that hard. And that's not some weird ego trip like some people try and say, it's just that I'd define it as unforgiving, rather than hard. The combat is a pretty simple affair for instance and won't take long to master, enemies tend to have set attack patterns and a few attacks. Once you learn them and learn what to do it's not really that difficult. You can switch armour/weapons to make use of enemies weaknesses (which you'll need to do, if an enemy can't be blocked there's no point keeping your heavy armour on) But! That one time you mess up a dodge or misjudge how much stamina you have, the enemies hit damn hard, you can get chain-stunned and killed very quickly. So that's why I define it as more unforgiving than hard, especially with the survival-like moments I mentioned above. Dark Souls punishes mistakes a lot, but it doesn't go out of its way to make mistakes a likely affair. Fights require more planning than just running in.
But yeah, I love Dark Souls 2, but the original is an incredible game. I think you'll enjoy it once you stop thinking of death as a bad thing; death is how you learn. Once you die, you don't repeat that mistake, and learn from it. I think gamers who are the type to throw their controller down in a rage when they die might not enjoy Dark Souls. If you're a bit more patient, and love RPGs, you'll be hard pressed to find a better one.