Anna is a first-person horror game set in an abandoned house. It is experienced by the male protagonist in an environment he remembers from his nightmares. The player explores the house and its immediate surroundings to find out more about the character Anna and events from the protagonist's past. It is an adventure game that is built around solving puzzles to progress in the environment. Objects that can be interacted with are highlighted in red when the cursor is moved over them. Players have full freedom of movement and can crouch, examine, pick up items or use them. Collected items are stored in an inventory where they can be combined or used in the surroundings. In addition doors and drawers can also be opened by a click-and-drag technique.
There are three endings in total, but instead of leading to a different conclusion at the end of the game, they are based on how deep the madness is experienced. So if the player can get past the initial ending — not triggering it — additional rooms in the house are opened up and additional game content becomes available. That way the game is split up into three equal parts and to access all of the content the final ending needs to be reached. The game is inspired by ancient legends in Val D'Ayas in Italy and its location is set between Champoluc and Periasc.