It was developed by manga artist Hato Moa's dōjin circle PigeoNation Inc., and is the successor of a Flash game of the same name she created for April Fools' Day in 2011.

Hatoful Boyfriend is an interactive text-based visual novel that follows a branching plot line, with the player's decisions determining which of the game's multiple endings they receive.

The game is set in a version of Earth populated by sapient birds, and its main story follows the player character and protagonist—the only human attending St. PigeoNation's Institute, an elite school for birds—as she finds love among her avian acquaintances.

[1] Bad Boys Love, a hidden alternate story mode, opens with the discovery of the protagonist's corpse, after which the player follows her best friend Ryouta Kawara as he investigates the circumstances of her death and unravels darker conspiracies surrounding the school.

Gameplay in Hatoful Boyfriend is similar to most other visual novels for the PC, with the controls limited to the mouse and the only interactions being clicking to forward the game's narrative or to choose between multiple plot choices.

If the player obtains all other possible endings prior to starting Bad Boys Love, an extended epilogue plays after the game's credits upon completion of the scenario.

[2] Hatoful Boyfriend is set in an alternate version of Earth in which sapient birds have seemingly taken the place of humans in society for reasons that are hinted at, but not fully explained in the dating simulation portion of the game.

In Bad Boys Love, it is revealed that Hatoful is set in a post-apocalyptic, dystopian future—in which a pandemic of a deadly, mutated strain of the H5N1 virus, or bird flu, nearly wipes out mankind in the year 2068.

[10] The game's story takes place primarily at the St. PigeoNation's Institute (聖ピジョネイション学園, Sei Pijoneishon Gakuen)—a bird-only high school located in the fictional Japanese town of Littledove Hachiman City (小鳩八幡市, Kobato Hachiman-shi)—long after open warfare between humans and birds has ended.

[28] The story of the dating simulation portion of the game follows the protagonist, and the inter-species love and hijinks—of both the mundane high school and quasi-anthropomorphic bird-specific varieties—that ensue as she draws the attention of and attempts to romance one of a number of eligible birds she comes in contact with over the course of the year.

[30] A siren sounds and there is an order to evacuate to the gymnasium, where Ryouta overhears other students mention that more pieces of a human corpse were found in the other print boxes.

Doubting the headmaster's explanation of a natural disaster occurring, Sakuya and Ryouta resolve to figure out the identity of the protagonist's killer and leave the gymnasium, discovering a large metal dome surrounding the school.

When he regains consciousness, he discovers the protagonist's bloody student ID—now with concrete evidence, Ryouta prepares to confront the doctor and Yuuya, only to find that Sakuya had left to do so alone.

Upon discovering documents revealing that Operation Hatoful was a Hawk Party project into developing biological weapons for use against humans using the school as an experimental facility[42]—with a focus on a strain of H5N1 almost immediately lethal to humans dubbed the Charon virus—Nageki recalls that the fire was caused by his committing suicide by self-immolation after months of forced experimentation in order to destroy and remove any trace of the virus, which was isolated in his body,[43] and that researchers often went in through the chemistry preparation room.

[47] A broken Ryouta submits to Shuu's offer of becoming a living weapon of mass destruction after these revelations, and a struggle ensues during which the protagonist's spirit intervenes.

[48] Shuu admits defeat and offers to lead them out of the school through a safe passage, but Kazuaki pulls out a gun and shoots him as the group prepares to escape.

They reunite with the other characters and exit the school along with the other students and faculty brought there by Mister One; however Ryouta, now thoroughly infected by the Charon virus, elects to stay behind in cryonic storage until a cure is found.

[54] If the extended epilogue is unlocked, it is revealed that Yuuya survived being poisoned long enough to receive an antidote,[55] and the game's closing lines imply that with Shuu's cooperation, a cure for the Charon virus has been developed.

[58][59] She first came up with the concept for Hatoful as a 2011 April Fools' Day joke: despite her lack of familiarity with the genre,[57][58] she initially intended to create a parody of otome game stereotypes.

[57] Hato's approach towards the game's writing was "to create something that seems ridiculous and crazy at first glance, but that once you look into the world, you would fall into the depth";[58] however, resolving the darker elements of the plot, particularly the Bad Boys Love scenario, with facts established in the quickly conceived and largely comedic pilot proved to be difficult for her, with inconsistencies in the overall timeline becoming a major concern.

Several locations and personalities featured in the game directly correspond to real life venues and people—for example, blogger Brian Pigeon is mentioned as one of the Hatoful world's most influential writers.

The demo version contains basic routes for seven of the love interests, and also functions as a benchmark for players to assess if the full game will run on their computer before purchasing it.

[75] The remake was also included in the Humble Bundle pack for Valentine's Day 2015, which exclusively featured dating sim games, along with a Hatoful Boyfriend pillowcase for the highest price point option.

[105] Each episode consisted of four segments: Hatoota (はとおた), a normal talk corner, Hatalk (ハトーク, Hatōku), in which various questions regarding life as birds were answered, Koi no Denshobato (恋の伝書鳩), in which lines from the game were read, and The How and Why of St. PigeoNation's!

[112] As a dōjin soft title, Hatoful Boyfriend was created on a limited budget and had even more limited promotion; however, due to strong word of mouth on Twitter and other social media[57] Hatoful has enjoyed a degree of commercial success, especially considering its minimal production costs—with Mado no Mori reporting that the game was a "popular title" whose physical CD-ROM copies "consistently sold out at dōjin markets and wherever it became available for purchase",[123] and 4Gamer.net noting that the game disk was difficult to purchase due to overwhelming demand.

[126] In an article discussing the E3 announcement of the 2014 remake, Carly Smith for The Escapist remarks that Hatoful Boyfriend is "absolutely hilarious", but recommends that players "start the game for a laugh, but stick with it for a ride you wouldn't have expected by looking at the cover".

[2] Alexa Ray Corriea's Polygon review of the remake gave it an 8 out of 10, concluding that the "witty dialogue and absolutely bonkers scenarios are genuinely fun to discover, and the handful of different storylines make repeated playthroughs worthwhile".

Mentions of the game's "bird romance" spread through Japanese social media, leading several news agencies and publications to report on Hatoful and the "newness" of its premise.

[84] In a retrospect, Jeffrey Matulef for Eurogamer remarks that Hatoful Boyfriend's "outlandish premise caught on and the English speaking world demanded it not be left out of this surreal creation",[130] while Robert Fenner of RPGFan compared it favorably to Hiroki Azuma's writings on database consumption, praising the game as a "fierce deconstruction as well as a tender celebration of dating sims".

[131] Several Japanese commentators have also noted the game's overseas success, especially following the E3 announcement of the remake by British developer Mediatonic and American publisher Devolver Digital.