Röki is an adventure game inspired by Scandinavian folklore. The protagonist is the young girl Tove. She lives with her little brother Lars and her father Henrik on a house on top of a mountain in an undefined location. Something has happened to her mother Eva and her father is still mourning. He spends his days sleeping in his chair and drinking, while Tove has no choice but to look after her brother all the time. One night the siblings wake up to a giant monster breaking through their bedroom window. They have no choice but to leave their trapped father behind and escape on a sled down the hill, looking for help. Lars disappears and Tove then has to explore a deep forest and befriend magical creatures to find clues on how to rescue her brother.
Tove is controlled directly. When she approaches a character or item in the environment where interaction is possible, it is highlighted and an interaction prompt appears. Tove will then start a conversation, examine something or interact with it in another way. Certain items can be picked up and are stored in an inventory. There they can be combined or used in the environment. This is done by dragging the item into the environment and then releasing it at the desired location to trigger an interaction. This is the main mechanic to solve the puzzles in the game.
The game is fully 3D. Tove is able to sprint and a button can be used to highlight all elements in the environment that allow for interaction. There is also a journal that consists of four parts. There is a map that shows the different locations with the ability to move between them. Notes contain Tove's thoughts about the events and contains important clues about what to do next. Loot is an overview of optional interesting elements Tove discovers in the environment. Badges are the game's achievements. The game is non-violent and it is not possible to die. Later in the game additional mechanics are introduced for certain sequences such as masks that alter how the environment is viewed or can be interacted with, and a part where it becomes possible to switch between two characters introducing cooperative puzzle-solving. While there are some dark elements from Nordic folklore, the game strives for a creepy-but-cute character design. There is no voice acting, but short, universal vocal sounds are often used to support the text.