Dishonored: A supernatural zero kill run stealth game

Dishonored is another dark game series involving supernatural assassins and graphic violence— but one which also gives players freedom of choice to use unconventional strategies, including the option to win the entire game without killing anyone.
Screenshot from Dishonored (in which crossbows can reportedly be loaded with nonlethal "sleep bolts")...
This is another one of many "contrarian" titles that we wouldn't have guessed was playable with zero kills unless we'd been told about it. In fact, we initially second-guessed that it really was a zero kill run after seeing gory screenshots of what most players were doing in the game— until we found interviews in which the developers themselves confirmed that Dishonored most definitely can be completed without killing anyone. Apparently not only is a zero kill run possible in the game, lots of special effort went into implementing this, and one of the designers mentioned that a disproportionate amount of their effort probably went into making the game work well for zero kill players.

One article we read mentioned that the stealth system in Dishonored was originally based directly on inspiration from Thief, until the developers made various changes to implement their own ideas, which include a creative array of supernatural powers and abilities. These can be purchased using runic whale bone artifacts, and include the ability to slow time, knock enemies down with gusts of wind, or see through walls. There are also "earthier" nonlethal solutions: Following in the footsteps of the 1980's arcade machine "Tranquilizer Gun," the player can load crossbows with "sleep bolts" that act like tranquilizer darts to put enemies into a deep but non-lethal sleep.
Screenshot from Dishonored
An NBC news feature on the game ("10 Tips for Playing Dishonored Without Shedding A Drop of Blood") interviewed one of the designers, who said that implementing a zero kill run through Dishonored was something they originally planned to include to some degree, but that after telling more people about it, they got an enthusiastic positive response and "realized that it was something that people really wanted. And so then we made it a mandate to make sure that we approached the entire game with non-lethal options."
Some nonviolent NPCs
In some cases, the game provides opportunities to eavesdrop on various characters to acquire vital information (such as combinations to locks, or locations of secret entrances), but also to provide more character interest: One of the designers mentioned that they had deliberately tried to include material to suggest to players that NPCs they might otherwise have considered killing had lives beyond their obvious role in the game, so that players might think more carefully about sparing them.

One of the designers also said they had to make special efforts to preserve a scene near the end of the game, in which players who went on indiscriminate killing sprees ran the risk of being betrayed by a key character who otherwise would not have turned on them. (Apparently they were under pressure to cut the scene due to fears that gamers who like going on indiscriminate killing sprees would be upset with the game if their actions turned out to have negative consequences.) The Wikipedia article quoted the Dishonored developer as stating: "Everybody just wants to be told in a video game that you’re great, no matter what you do. If you slaughter everybody – you killed the maids, you killed the old people, you killed the beggars – you’re great, here’s a medal, you’re a hero... We decided that sounds psychotic. It doesn’t match our values... What we wanted was to let you express yourself in the game, but to have the world react to that, at least in some way."

Dishonored is definitely a title we'll be playing as soon as we can. One caveat in the meantime is that we're not so sure about just how little violence you can actually get away with (as opposed to the infliction of fatalities)... The article that introduced us to the game mentioned that some of the non-lethal solutions one may be obliged to use to complete the missions were "horrific," despite the fact that they didn't result in a kill...
Nonetheless, it looks clear that Dishonored still achieves the zero kill run standard, that lots of special thought and effort went into making this very thing possible for players like us, and that (like Thief) the game even has a built-in scoring system to reward players skillful enough to win the whole game without killing anyone. (In Thief, this was known as the "Ghost" rank, and in Dishonored it is apparently called the "Clean Hands" achievement.)