Brothers is a single-player cooperative game where the player controls two brothers independently and simultaneously. The game starts in a village where the two young brothers live. Their mother drowned in the sea and their father is ailing. The two set out to find the Water of Life, which is said to hold the power to cure their father. Both brothers are controlled separately for movement and actions. The game strings together various scenes where the brothers must solve puzzles by helping each other, for instance by pulling levers, dragging items, distracting dangerous characters or operating a catapult. Not by controlling them separately, but often both at the same time. Next to movement they can also climb, hang from ledges and slide down. There are a few enemies along the way, but these cannot be fought directly. Instead, a more inventive approach needs to be found.
The game focuses on exploration and especially environment-based puzzle-solving to progress. The game is shown with a third-person view, often shown from a distance or above, and with a fixed camera. The level design is linear with a single path to progress. It also contains various sequences not related to the main quest where the brothers have fun together, to establish the atmosphere. The environment has a fantasy-like atmosphere with different locales such as villages, mountains, a sequence where they travel by boat over a river, a frozen landscape etc.