That Dragon, Cancer is an autobiographical tale that focuses on the Green family's five year old son, Joel, who loses his life due to terminal cancer. Joel Green was diagnosed with atypical teratoid rhabdoid tumor (AT/RT), a tumor usually located in the brain, at twelve months old. The game jumps in time between Joel's diagnosis and his death on March 13, 2014 at age five. Real life events are told through the perspective of Ryan and Amy Green, switching between first and third person, including real life recordings during Joel's life. Due to the autobiographical nature of the game the events are raw and personal such as: a day in the park with the family, holding Joel during chemotherapy, or a sleepless night where Ryan tries to pacify a crying Joel as he suffers from dehydration due to his sickness.
The game explores Ryan and Amy's emotions and faith while raising Joel. Player interaction is done through fantasized settings like: a cart racer with Joel driving through a hospital, Joel flying through the air with hold onto tumor balloons, and a 2D side-scroller where Joel fights a dragon named Cancer.
The developers of That Dragon, Cancer were Ryan Green, Amy Green, Josh Larson, along with a small group of designers. Joel was diagnosed at twelve months old with doctors telling the Green family he would only live either a couple of weeks or up to four months. Joel would continue to live for four more years. Development started when Joel was four and was meant to explore the Green's family uneasiness not knowing Joel's fate. However, when Joel passes away the game was almost completely rewritten to focus more on interactions with Joel with a more definitive ending.
That Dragon, Cancer was funded in part through a Kickstarter campaign that launched in November 2014 that raised $104,491 through 3687 backers as well as through as partnership with OUYA, which helped them bring the game to that platform.
That Dragon, Cancer takes place across 14 scenes that each either represent an actual time Joel's fight with cancer or are an analogy to represent the way Joel's parents are dealing with his sickness. The only controls are to click around environments inspecting and interacting with different people or objects to either advance the scene or gain deeper understanding of the situation. Outside of this there are few exceptions that have the player fighting through a small arcade level and racing through a short kart racing section. It is largely a one button game.
The 14 vignettes in the game each serve to expunge the inner monologue of the various people who surround Joel as he fights cancer. The timeline begins with Joel seeing idiomatic symptoms and runs through the diagnosis conversation and various stages of Joel's treatment. These events also serve to give the characters an opportunity to express and work through both joy and grief as well as different levels of religious faith.
When the gameplay changes away from its point and click base with kart racing and 2D side scrolling, the tone also changes, perhaps meant to flashes of happiness and joy that were seen in what is overall a very dour story.
Directors Malika Zouhali-Worrall and David Osit captured the process of making That Dragon, Cancer in their documentary Thank You for Playing which was saw a limited release on April 17, 2015. Episode #50 The Cathedral of the Gimlet podcast Reply All also gave a look behind the curtain of making That Dragon, Cancer that utilizes Thank You for Playing, the game itself, as well as new interviews with the principal development leads.