Re: Agency and failure
First of all, I think that the concept of 'failure' has not been clearly defined in relation to games. I ought to have been more specific in my previous post since this term is so commonly linked to game mechanics. Some commenters seem to have reduced my point to this type of failure, and even Rowan refers to failure as being inherently defined by player choice.
But games are innately adversarial, either player versus the rules, or player versus the game writer/designer. For failure to be considered valid, the player must fail because of a choice she made. Failure that is simply imposed by the rules or game designer is not considered valid, not considered fair.
My example from Neverwinter Nights 2 was a type of writer-designed failure that does not interrupt the flow of the game in the way that some commenters think failure will do: because they are considering absolute situations in some cases (ceiling collapsing on your hero's head, or ultimate boss crushing you to a pulp), or because they are assuming the position of the almighty hero we have been accustomed to. In NWN2, the pinch of salt that I am advocating for was Bishop's betrayal and what it symbolised: even though you might be a hero, you are not entitled to succeed in every endeavour. Some of your followers will not agree with you. You cannot please both Sand and Qara (the level-headed mage and the volatile sorceress).
The impression I get from most AAA games these days is that you are cast in the role of conqueror, allowed to intervene in every political and personal issue for no disbelief-suspendable reason other than you being the PC. That is the feeling I get every time I play Shepard. How is it possible that one single human being might affect the destiny of so many species, with a few words? Traditionally, the scope of a player's influence upon the world was not as wide, and it required less words and more action. That is how heroism was justified. I am thinking of NWN 1 and 2, the Baldur's Gate series, etc. For me, it is easier to accept an omnipotent kind of heroism that springs from my combat prowess, because I really did earn that through countless save and reloads, than a galactic-wide parliamentary influence coupled with extreme displays of charisma in more intimate situations. Can anyone in her crew not fall head over heels for Shepard? Can we see any instances of real disagreement, perhaps leading to dissension or even betrayal? Mass Effect needs a dosage of this type of failure to make me identify with the heroine.
I want to acknowledge Dragon Age 2 here for what I believe are better-developed interpersonal relationships which allow for disagreement, even though their consequences are not as fully carried out as in older games (Baldur's Gate is notorious for NPCs free-will). There are great narrative experiments going on here in the gaming field, especially coming from indie developers. I believe that there is a specific language that only games are endowed with, and which we have not yet fully exploited. But I do not approve of dismissing the achievements of other media and engaging with games as a completely separate entity: that is very disempowering for the gaming industry. That is why I find it necessary to call attention to aspects of games that could benefit from the progress of other fields in the way that stories are told, so that we can devise how to adapt their rules to our own medium. Games are different, but only God creates ex nihilo.
Players can never actualize the role of a traditional protagonist which makes mistakes due to her human nature, because players are not engaging in a theatrical identification with their avatar, but using it as a vehicle of their will to explore and affect the world around them. Only deviant gameplay in which the player willingly allows herself to fail for roleplaying purposes counteracts this view. In any other instances, we tend to seek the best possible outcome, and we should keep trying to do so. There is nothing wrong about wanting to be heroic. What is wrong is the extremely pliable world that we are offered, where we can be archmages, master assassins, vampire-werewolves, and anything in between those and Dragonborn. Nevertheless, some silly unbelievable narratives such as what The Elder Scrolls offers are fine, as long as they do not constitute all of the hero-themed games out there.
A failure in the sense of player misperformance is also possible and can be narratively rich. Consider the death mechanics in Ultima Online, which involved much more than a corpse-run, or in Planescape: Torment; or even in palaeolithic WoW, which enabled you to talk to a ghost in Blackrock Mountain for a quest.
Finally, the idea of failure being anti-climactic, as observed by some commenters, is precisely what I do not advocate for. Failure can and should be embedded in the story in such a way that it enforces its themes. Casualties in war, the example of Ashley/Kaidan's death, is relevant within the themes that Mass Effect engages with, and has a climactic quality. I am sure you have read plenty of novels whose conclusion was not light-hearted but it was befitting nonetheless. Some characters, some plots, are destined to fail, and no other conclusion would have done them justice. I am not sure we can apply this as crudely in games for the reasons some Rohan and his commenters drew — players not accepting imposed failures, and seeking perfect 'scores' —, but it is worth considering in discussion to find how it might improve our games.