Shaun Inman's Vonneguts & Glory is a FPS homage to Slaughterhouse Five
So it goes - backwards

Shaun Inman, the indie designer and developer of Mimeo and the Kelptopus King, has submitted a first-person shooter based on Kurt Vonnegut’s Slaughterhouse Five to Apple for App Store release.
Dubbed Vonneguts & Glory, the FPS game and its incredibly retro graphics have the player live the life of their pixelated protagonist in reverse.
This theme is central to the award-winning novel Slaughterhouse Five where main character, Billy Pilgrim, becomes ‘unstuck in time’.
As you might imagine, how this maps out to Vonneguts & Glory is a bit confusing.
You restore your character’s health by ‘unattacking’ enemies, and ammunition is similarly restored by ‘unshooting’ them. Unattacking with a bloody knife, for example, cleans it off.
Poo-Tee-WeetInman’s artistic approach to the first-person shooter was created as an entry in the 7 Day FPS Challenge.
It created by Inman (and Inman alone) in the span of a week, which helps helps to explain the current browser-based version’s short duration.
Although Inman has not indicated whether the submitted iOS version would see any extended gameplay or development, he has noted that Vonneguts & Glory will be available for free pending its approval by Apple.
Via: The Verge