Décorum might be about solving a puzzle, but it’s really a game about communication and compromise. The real challenge isn’t just solving the problem with the limited information you and your players have; it’s dealing with the frustrations that will inevitably occur when your partner does something that messes up your plan. In order to be successful in Décorum, there will come a point where both players will have to let go of their initial strategy for how they were going to finish the board and start paying attention to what their partner is doing instead. By introducing and providing an incentive to resolve conflict, Décorum mechanically encourages (or even requires) a positive form of compromise.

Each player draws a "Scenario" card that lists a set of criteria of what types of décor a room must have or cannot have. For example "No room may contain a lamp" or "Every room must contain a wall hanging". Players keep their criteria secret.

The play surface is a board displaying various rooms in a house. Each room has multiple items that can potentially be placed in the room. Players take turns placing, moving, or removing colored tokens on the board, where each token represents an item of home décor. Each token placed may conform with, or violate, the other players' criteria. After each token is placed, other players may state they like the item of décor, as placed, or they do not like the item of décor, as placed. Further discussion or explanation is not allowed.

The game ends when all players' criteria are satisfied.