The word of the day is "failure." What does it mean, in the context of a video game? Do I "fail" at Dark Souls when I die a dozen times in a row? Probably not, because dying is a central part of the game's marketing. I'm supposed to die. If I didn't, I wouldn't be playing the same game as everyone else. Dying is normal, and not something I should allow myself to get upset about.
Maybe that is the game's failure mode. Maybe there's an intangible barrier between zany, self-deprecating mayhem ("holy shit, that dragon came out of nowhere and one-shotted me before I even had a chance to react - this game is crazy"), and grim, self-loathing despair ("I keep getting killed by random, faceless, undead - I really suck"). Failure then, would be crossing that line in your heart. You fail Dark Souls when it stops being fun.
But that's pretty abstract. I think it's more likely that you "fail" the game only when you give up. Dark Souls has a story, and that story gives you a goal to work towards, and so long as you keep playing, that goal is never notionally out of reach. It only becomes impossible once you stop.
Sounds good. Except that there is a lot of room in the words "notionally possible." It's an idea big enough to contain "functionally impossible." You could, for example, repeat the same level over and over again forever, always dying to the minion squads before you get anywhere, and fail 90% of the time to recover your lost xp, and thus never get any more powerful, and always be confined to a narrow radius around your bonefire.
And while that has not happened to me yet, my experience of Undead Burg has certainly convinced me that it's a possibility. I've noticed a pattern where I will uncover a new area, immediately get killed by whatever is lurking therein, and then have to spend 3 or 4 lives to get back to the place I was before (checkpoints are few and far between, so every time you die, you have to start back at the same, eventually quite isolated, location), where I then get killed slightly less quickly and thus have to repeat the process again and again until I get it right. And then I push a little bit farther, find a new area, and get killed.
I've yet to get ahold of the rising feeling of mastery that is a characteristic of these sorts of high-end action games. Usually, when I play a level of, say, Viewtiful Joe and it proves to be beyond my abilities, I can repeat that level a dozen times and gradually, the rhythms of the the level imprint themselves in my subconscious, and things that were once difficult become trivial. Eventually, the level itself becomes rote.
That has not happened to me with Dark Souls. I'm still finding the low-level monsters to be a serious threat. I think it's because the checkpoint system is much less generous than in other games. So, I'm not just repeating the "difficult" parts. I'm also repeating the parts I could get through relatively easily, and by the time I get back to where I'm having trouble, the muscle memory has faded. And when I'm "successful" it means that there is a longer delay between the times I get to practice the early fights, and while sheer repetition means I'm able to get through them, I am not at all consistent in the resources I use in the process. So, beating a boss in Dark Souls is not just about taking on the boss, but also about learning the whole damned level well enough that you're not crippled by attrition by the time you get there.
And then, when you beat it, a dragon comes out of nowhere and flames you to death before you have a chance to react.
I worry that eventually, the chain will get too long for me, that the really tough nut will be at the end of a series of fights that I'm just barely good enough to get through, and thus I won't be able to accumulate experience (due to losing it all in a place not amenable to consistent recovery) or arrive with enough resources to win, and that as a result, I'll be stuck in an endless cycle of loss. That, in essence, I will "fail" at Dark Souls.
(As a meaningless aside, let me vent a little about Games for Windows Live - WTF is up with games making you sign up for various proprietary services when you try and play them - it should have included an option to opt out, but when I tried, it told me my game wouldn't save, and thus I swallowed my pride and went with it, but this now makes the fourth PC online service I've had to make an account for alongside Steam, Origin, and uPlay. I'll never be able to remember all these passwords).