Killer7

Killer7 is definitely a game that I would not consider 'fun', but one that demonstrates the potential of videogames as a storytelling medium. You could tell this story as a movie, manga, novel, etc. but it wouldn't be quite the same narrative as it was in this game. The various tools the game uses--the cell shaded graphics, the inspired/unique sound design (the acoustic guitar strum when items appear; the mechanical voice saying "bullet"), the intentionally awkward controls (at first I hated them, but after awhile they seem very deliberate), the mix of anime and CG cutscenes, the interactions in the 'save rooms' (the TV channel idea is charmingly bizarre)--could never be done in any other medium.
I know people are starting to apply the auteur theory to videogame designers, but this is a case where I feel it truly applies. You couldn't get a game like this out of any designer other than Suda51. As the game is a surreal, complex mess that I'm still trying to unravel after the ending, it reminds me a lot of a David Lynch film, open ended meanings and "leave it up to each viewer/player to decide for themselves" and all. In a similar fashion to how you always get the impression Lynch had a hand in everything in his films from the sound scoring to the camera angles to the production design to the dialogue, you get the sense that Killer7 was entirely Suda's vision brought to life.

This isn't to say that Killer7 is a flawless masterpiece. There's a big difference between an 'art' game and a great 'art' game. Just as I've never seen a movie quite like Lost Highway but don't consider it a great movie, I've never played a game like Killer7 but don't consider it a great game. This raises a whole 'nother side debate of why I play certain games, and what I hope to get out of them. Killer7 is a unique, inspired, and utterly memorable experience (experience being the key word here) but playing it is often a frustrating chore. Even though you effectively can't lose because of the Garcian character, who can instantly revive dead characters by recovering their bodies, Killer7 is still a difficult-for-the-wrong reasons gameplay experience. Enemies that can instantly kill you, or that can get off cheap hits on you because you just came through a door, are something the entire medium needs to leave behind if we want more people to stick with 'art' games like this. I don't mean that such games need to be stupidly easy, but they should at least make getting through the narrative as easy as possible.
As it's a mix of a rail shooter, survival horror, and an adventure game, Killer7 doesn't do any of these pieces particularly well, but as a combined package, it's frequently brilliant. This especially comes to a head with the boss battles, which range from unique spins on the tried and true "expose/shoot the weakpoint" to a High Noon-esque duel with a dove as the timer to a predetermined, fighting game-style tournament that you play but have no direct effect on to a "final" boss fight in which you win by letting all your characters die. Kind of.

All the while, the game is playing with the conventions of the above genres, and videogames as a whole. Just as Earthbound could be taken as a parody of RPGs, Killer7 constantly undermines your idea of what a game can be and what's supposed to happen during a plot. Much as Lost Highway starts off as a mystery about the disappearance of a musician's wife before things quickly take a turn for the surreal, Killer7 starts off about a team of assassins assigned to stop a terrorist group before quickly going off the deep end. It is absolutely post-modern, and skirts dangerously close to being a meta-game at certain points. Though it may not make a whole lot of sense to you, but you'll never forget it. The levels you go through--particularly the school and the Japanese-style mansion/house--have a surreal, dream-like atmosphere that matches the ghostly characters who talk to you with their distorted, robotic voices, creepy monologues out of which you can occasionally catch a intelligible word or two.
If you approach Killer7 like you would any other game, trying to overcome the enemies and power your way through to the end, you're missing the point. Even if it is ostensibly a shooter, it's one of those games--like Silent Hill 2, Earthbound, and Shadow of the Colossus--which you're tempted, indeed encouraged, to think about when you're done playing, and to go back to over the years to catch new details. To take your time with the game, linger in its environments, and puzzle at the complicated story (and backstory) as well as the series of endings, is to fully understand what the game was trying to do. To put it succinctly, Killer7 is a game you don't play, it's a game you experience. It has its flaws (after all, it's one of those titles that the same reasons I give for loving it, other people give for hating it) but as an experience it remains one of the best the medium has to offer.