Natural Doctrine is a tactical, turn-based role-playing game set in a fantasy universe where humans fight other races. The player controls the guard soldier Geoff who works out of the fortress city Feste. Initially he goes after a number of goblins to gather resources, which is the start of a large story. The player eventually assembles a party of up to ten different characters with classes such as all-round warrior, apprentice, battle medic, sword specialist, and sword master.
The gameplay involves strategy and planning. From a top-down world map, different locations or scenarios are available. During battles, characters are shown from a top-down or third-person perspective. Movement is based on grids, and characters have various offensive and defensive actions available based on their class. The position of a character in the grid also plays a role, as specific actions become available or characters can act out of their turn.
The game features a skill tree system where characters can level up and improve their abilities by earning experience points. Each class has its own unique paths to unlock, allowing players to experiment with different builds or strategies. The game also includes obstacles in the environment that must be taken into account, such as friendly fire and unwanted linking effects.
Players can enjoy the game in single-player mode, or team up with others for competitive and cooperative online multiplayer games. Fights are similar to single-player portion, but they involve collecting and building a deck of cards that becomes stronger over time. The game supports cross-platform multiplayer and cross-save functionality.