One eleven is a dark detective story about twelve lonely people who, by chance, find themselves in the same house with a mad maniac. Who will be the victim and who will be the killer? Be attentive and courageous, and solve the riddles of One Eleven.
The game combines elements of a detective story and a dating sim, focusing on the interactions and decisions made by the player-controlled protagonist, who finds themselves trapped in a mansion with eleven other characters, one of whom is a killer.
The core of the gameplay lies in the dialogue system and the choices the player makes during conversations. The game features over half a million words, providing a vast number of dialogue options. The protagonist's words can have significant impacts on the relationships and trust levels with the other characters, affecting the progression of the story and leading to different outcomes, including multiple possible victims and killers.
In addition to the detective aspects, the game incorporates dating sim elements. Players can develop relationships with several of the female characters, earning "relationship points" through their dialogue choices. These points determine the level of intimacy and the potential for romantic outcomes with each character.
The game offers two difficulty levels: "Normal" and "Hard." The "Hard" mode disables the ability to save progress and removes the "Karma" system, which tracks the relationships with the other characters. This increases the challenge and encourages more careful decision-making, as mistakes can have more severe consequences.
A key feature is the randomly generated beginning and the ability for the player's decisions to lead to vastly different scenarios, with varying victims, killers, and narrative paths. This promotes high replayability, as each playthrough can result in a unique experience.
While the focus is on dialogue and decision-making, players can also explore the environment and gather clues. Interacting with various objects and locations in the mansion can provide additional information and insights to aid in solving the mystery.