This will be very, very long I suspect. There will be a short conclusion at the very end. Two games have made me want to cry (or become unreasonably angry): Red Dead Redemption Dragon Age: Origins

A few have made me ask questions of morality: Bioshock KotR Red Dead Redemption Dark Souls (Of all games...more on that later.)

However, in "masterpiece" classification, I'd say the most important assets are that feeling of emptiness from completing a game and the suspicion that one is, in fact, playing art. One or both of these occurs and I'd call it a masterpiece. That's happened in:

Red Dead Redemption Legend of Zelda: Ocarina of Time Legend of Zelda: Twilight Princess The Wolf Among Us Dragon Age: Origins Dark Souls

To keep my justifications brief, I'll focus on Red Dead Redemption and Dark Souls. Red Dead Redemption is a masterpiece because it forces the player to empathize with a very realistic cast of characters before ripping their lives apart. The beautiful, barren, but immersive world provided an apt backdrop to the equally beautiful and solemn tale of John Marston. It serves as an elegy to the American frontier, but also a surprisingly human story of what someone is willing to sacrifice for their family. The player must feel Marston's pain at losing his family at the beginning, and must see how he feels about his quest, his feelings of uncertainty, and his determination to stay on the path of good. His descent from this path at the hands of the Marshalls creates a tragic hero of the Cowboy. He is not the rugged, robotic cowboy of thousands of spaghetti Westerns; Marston is an aging father trying to do right in a harsh land full of harsher individuals. The player watches his power slowly slip and by the end of it are left in somber emptiness. That is why this is a masterpiece: As the credits roll, have no doubt people will remember hundreds of hours of kicking tumbleweeds through Armadillo, rooftop fights with the lawmen of Blackwater, and the beautifully rendered scenes of John as a father, trying to teach and protect his son, Jack. They will remember, as it were, his life. It will not seem fictitious, but it will still seem over. Over too soon.

On the other hand, Dark Souls is a masterpiece for an entirely different reason. It does not even attempt to convince you its characters are plausible, its locations hidden in some corner of the world, nor its plot possible. It, instead, offers the player a role looking at life and death and good and evil through a lens not provided to men in life nor in other media. As one dredges and wades through the lifeless, yet enchanting and oft-unforgiving landscapes of Lordran they meet characters of gray morality and become heroes of a darker shade.

Is Lautrec evil for wanting power? Are the hollow evil for standing in your way? Are you a hero for being the Chosen Undead? All characters in Dark Souls present a tone very popular in East Asia's ancient mythos: Melancholy. It's a disparaging look at mankind. The people of Lordran are wretched and self-interested. Hollows attack the last bastions of sanity, people are cold, hungry, and tired, yet, no one cares. The true heroes, Oscar most apparently, die horrific deaths. For saving a stranger from eternity in a prison cell, Oscar is stabbed and left to bleed to death and hollow; In contrast, the player will often will not think twice about murdering his fellow Undead for a weapon or even their very souls! This is the hero of mankind, a Chosen one, who would be the savior. It is a purposeful statement about the product leader's view of mankind (or at least parts of it).

Dark Souls parallels Nietzsche. The one who becomes the Hero is the man who stops at nothing to become the most powerful of his peers, not the one bound by honor, morality (sklavenmoral, anyone?), or meekness.

In addition, it speaks volumes on life and death, though perhaps, less obviously. Life and death are annoyances on the Chosen Undead's journey, mere setbacks in a cosmic powerplay. It speaks a lot to fate, but more interesting to some, is the derived existential insight: In a world in which a sane man cannot expect love, hope, nor happiness, is life meaningful? FromSoft. argues, eloquently, some may add, "maybe." Living is a chore in Dark Souls. Every character in the game marches on, some to die, others to die repeatedly, in a quest to liberate themselves from the cycle. There is no victory. There is only sadness and determination to move away from that sadness. Only the Chosen, the one who determines to break the cycle rather than simply survive it, is able to make meaning of his life, either through power or sacrifice.

In this respect, Dark Souls is an artful masterpiece. It's abstract story and punishing gameplay make it a solid game, but it's bleak despondency and fuzzy ethics make it transcend button-mashing. For those willing to read it, it opens a book on human nature and the nature of life. It is an essay by Hidetaka in a form that rises above print and prose by putting its audience directly into the extremes of his viewpoint.

I've digressed I guess, but to conclude: Games can be masterpieces in different ways. Red Dead Redemption, for example, is a twist on the stoic, invincible frontiersman. By portraying realistic characters in a more-or-less historical setting and putting them on a crash course with the closing of their ways of life, Rockstar creates a lasting soliloquy on the role and death of the West, while offering a somber tale of a father's devotion to his family. In contrast, the hands of an artist can bring videogames to bring tangible, visible features to abstract ideals. Dark Souls does this: In bringing the ideas of existential existence and Hobbesian human nature to their extremes, FromSoft. brings these concepts to a much broader audience in an engaging way.

TL;DR: I ramble. A lot. The definition of "masterpiece" is subjective, but I call it something that leaves a profound impact on the way I look at something. In this respect, the "most masterful" masterpieces I've encountered off the top of my head are RDR and Dark Souls. In different ways, both studios bring tangible, visible aspects to the concepts and themes they seek to disseminate and allow the player to immerse themselves in them. RDR changed the way I think about the West and was beautiful. I read DS as an exposé akin to Nietzche or Kierkegaard. That's nerdy, and I accept that. XD