Planescape: Torment is a notch above (now legendary) titles such as Baldur's Gate and Fallout. And that speaks volumes for the game's worth. And this small notch cannot be justified by the unique (if bizarre) array of characters, the excellent voice-overs, the superb rendition of the gothic, in a slightly cyberpunk way, environments of the Planescape campaign setting. It cannot be justified by the breaking of the classic AD&D ruleset into a much more flexible character development model. No, these elements are more or less there, in every Black Isle endeavor that preceded or followed this game. It is the story itself, and the way that you, the player, uncover it. The hero is an immortal being with tremendous potential, and yet, it is easier to identify with him than with any other CRPG character, simply because you start off at the same point exactly: you know what he knows. Nothing. You meet people who seem to know you, like you, most often hate you or fear you. You go to places and see things you should be able to recognize, only you don't. You remember doing or discover you?ve done things that seem irrational, weird or outright evil. You're not out to save the world, not really. You're trying to save yourself. And this thing, alone, is a ground-breaking concept in the genre. Not only that, but you share a special relationship with most of the NPCs, which does not directly affect the story, at least not in a way that is obvious early on in the game.
There are few RPGs which can cause such strong emotions to the player (and none that can cause the same range of emotions, starting with horror and misery and ending in awe.