Battles in HELLCARD designed for cooperative playthrough, immersing you in the fictional world of dark fantasy. The user will have to try out a deck-building game that poses a challenge in randomly generated dungeons. Gameplay mechanics allow you to take control of a hero with certain skills and abilities to try to cope with the challenges in the dungeons of the Book of Demons. You have to put together a set and combinations of techniques for attack or defense while dealing with advancing enemies.

Combat skirmishes in HELLCARD are organized in a turn-based tactical mode, where you need to carefully monitor the situation on the battlefield. The player will have to move through deep and dangerous underground corridors, where aggressive creatures live. You can destroy your opponents using various spells and special techniques, depending on the selection of cards for a specific character. Protagonists are able to cope alone against monsters, or hire help in the form of companions.

Other gamers can become companions through multiplayer co-op, allowing them to work together to deal with opponents. Each level will be unique, generating conditions for the game randomly, leaning towards the traditional roguelike genre. When going on adventures, success depends on choosing the right strategy and thinking ahead, trying to predict the actions of your opponents.