Players control Cole Mason, an amnesiac surgeon trapped in a time loop. As Mason comes to in a research lab, he is required to operate on a patient who has a monstrous parasite growing in her. At various points in the story, which is presented via full motion video, players must choose between two options. Some choices reset the time loop with Mason's death.

Others reveal information about what is going on or advance the plot down different paths. Cinematic sequences are skipped over if players have seen them before. There are multiple endings. It includes a "streamer mode", which allows people watching a livestream to influence outcomes.