In Firefly Adventures, players take on the roles of the crew of the Serenity and attempt to complete jobs in the Eavesdown Docks of Persephone to earn the Credits they need to keep flying. The game is scenario-based, with each job having its own challenges, opponents, and victory conditions that the players must complete in order to succeed. Players can play a game with a single job, or chain them together into a campaign, using the credits they earn to equip their characters for the next job.
The game offers tactical action, which takes place on the double-sided map tiles, using three-dimensional container buildings to recreate the Eavesdown Docks. Each character in the game has two sets of abilities, depending on whether they ''act casual'' or ''act heroic.''
Firefly Adventures: Brigands & Browncoats will include ''casual'' and ''heroic'' miniatures for five crew members, as well as 10 different miniatures representing cowboys and thugs to fight against, double-sided board tiles, 3D building terrain, cards, and dice.