Hatoful Boyfriend is an unusual game that takes place in a post-apocalyptic future where birds have taken over the world, and the player, a teenage girl, is the only human student at a pigeon-run institute. The game is a visual novel that allows the player to interact with the characters by clicking on dialogue options. The game has minimal gameplay, but it rewards multiple playthroughs by unlocking documents that reveal more of the game's world and plot.

The player can romance several bird characters, and the game has thirteen different endings that depend on the choices made by the protagonist. After discovering certain endings, the Bad Boys Love mode is unlocked, which reinvents the plot with a horror twist. This mode explores the conflicted relationship between birds and humans and provides a more in-depth look at the game's world and plot.