Thorgal: The Board Game is a cooperative storybook adventure game. Players take on the roles of Thorgal, his wife Aaricia, their son Jolan, and Kriss —a deadly female warrior—, and go on a series of adventures. The game consists of 7 stand-alone scenarios, each taking roughly 90-120 minutes of play. Scenarios do not form a campaign nor have any legacy features, so they can be played by different playgroups and over an extended period of time.

Thorgal: The Board Game comes with a book of maps. Each scenario is played on a different map that players explore while fulfilling scenario goals and promises completely different adventures, hidden opportunities, side quests, and vivid characters. Players are free to choose whether they travel in one group or split to cover more areas at the same time. Each character gains experience during the game and advances their abilities. Characters gather resources and craft objects to help them survive in the dangerous world.

There is a storybook containing narrative descriptions of the encounters that Characters make in each scenario. The adventures described in the book are specific to each scenario and Character, with randomized elements offering higher replayability and allowing for repeated play. There are also Side Plots players can pursue to gain benefits and reveal additional pieces of the story.

Thorgal: The Board Game also has a unique action selection mechanism. In this new mechanism, actions have varying power depending on which other actions have already been taken. Players must carefully plan their strategy and sequence of actions taken, as this directly impacts the strength of the effect of each action.