The "extra life" was a fixture of early video games, a reward for skilled players that was imbued with the language of reincarnation. Players would not say they earned additional time to play, or a bonus turn, upon reaching a certain score. They were bestowed an extra life, a new chance at existence.
Death is not so frivolous in "That Dragon, Cancer," a video game about Joel Green, a terminally ill 5-year-old, and his parents, Ryan and Amy. It is a game about a single life — one that ends and then is gone forever.
The Greens, who live in Colorado, spent the past three years making the game with a small team of artists and designers. Ryan Green, who is a programmer, quit his job to work on the project. It is based on their own lives and that of Joel, who died while the game was in development.
"That Dragon, Cancer" is not the first memoir to arrive in the form of a video game, but it is probably the most ambitious.
"I feel like 'That Dragon, Cancer' is one of those breakthrough moments," said John Sharp, a professor of games at the New School and the author of "Works of Game," a book about the intersection of games and art. "I think we may look back at this game and see this as a touch point, a moment of rethinking what people can do with interactivity."
"That Dragon, Cancer" mixes animation and magical realism to convey the Greens' emotional state during Joel's illness. There is one dragon, but much of the game consists of re-enactments of mundanities like phone messages and hospital visits. Water fills a room as a doctor says there are no more treatments for Joel's cancer.
The game also uses documentary audio — taken from home movies as well as from "Thank You for Playing," a film about the Greens that had its premiere last year at the Tribeca Film Festival. Players hear Joel's laughter, and they listen to the prayers that his parents, who are Christians, shouted on the last night of Joel's life.
The interactions offered to the players of "That Dragon, Cancer" are relatively limited. Players mostly click to decide which part of a vignette — feeding ducks at a pond or escorting Joel through a playground — will unfold, and when to move on to the next part of the Greens' story.
The restricted controls are intentional. A go-kart race through a hospital frustrated some critics, Ryan Green said, because the unwavering speed of the go-kart is dictated by the game. "That's the point," he said. "All you can do is steer, hopefully."
Withholding some control from the player was an attempt to convey feelings of helplessness and despair. "One of the great strengths of video games is that automatically a player goes into a game expecting to have some agency," Amy Green said. "And it felt like the perfect way to talk about cancer, because all a parent wants is to have some agency."
Despite all the attention paid to "That Dragon, Cancer" — podcasts, magazine articles, a documentary film, millions of YouTube views of people playing it — the game's sales in its first month have been modest, the Greens said.
About 10,000 people have bought it, according to the website SteamSpy. That's a nice number for a work of creative nonfiction that arrives inside a dust jacket, but not for a three-year software project with eight people working on it.
By comparison, almost 4 million people own "Grand Theft Auto V" on Steam, the primary digital storefront for PC games, according to SteamSpy.
"I always tell people, 'You know those indie, artsy films that Ryan likes and no one else likes?'" Amy Green said. "'There are video games like that.'"