Hero Realms is a deck-building game that is a fantasy-themed adaptation of the award-winning Star Realms game. The game comes with basic rules for two-player games, along with rules for multiplayer formats such as Free-For-All, Hunter, and Hydra.

Each player begins the game with a ten-card personal deck containing gold (for buying) and weapons (for combat). You begin each turn with a new hand of five cards from your personal deck. When your deck is out of cards, you shuffle your discard pile into your new deck. An 80-card Market deck is shared among all players, with five cards being revealed from that deck to create the Market Row. As you play, use gold to buy champion cards and action cards from the Market. These champions and actions could generate large amounts of gold, combat, or other powerful effects. Use combat to attack your opponent and their champions. When your opponent's score (called health) reaches zero, you win!

Multiple expansions are available for Hero Realms that allow players to begin the game as a particular character (Cleric, Wizard, Fighter, etc.), fight cooperatively against a Boss, fight Boss decks against one another, or compete in a campaign mode that has you gain experience to work through different levels of missions.