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The Potential of a Digital Card Game

Card games have been around for over a millennium. That's 1000 years of exploring potential game designs for physical card games. In comparison, digital card games have been around for a decade. And even then, most digital card games are just ports of established physical games. Pure digital card games are few and far between. That is, games that are designed specifically for the digital medium. These games explore the possibility space of the genre in new ways. Hearthstone is one of these such games. It uses the possibilities of the medium to create a unique and compelling experience. Hearthstone's intelligent design sets it apart. By targeting the digital medium specifically it isn’t just good, it's an overwhelming success.

Persistent Damage

One of the most interesting and unique mechanics in Hearthstone is persistent damage. What might seem like a very simply decision, persistent damage is only possible in a digital medium. Playing with damage counters in a physical game would result in a board cluttered with beads, coins or dice. In the physical medium, persistent damage would make deciphering a board state extremely complicated. Because Hearthstone is digital it's able to update the numbers on cards themselves. The result is a clean and simple representation of a very complicated board. This approach to damage also opens up the game to some unique mechanics. The Priest Class for example is able to heal it's damaged minions. An interaction made possible because of persistent damage. And persistent damage is made possible because of the game's design for a digital medium.

Created Cards

Cards that materialize out of thin air are cool. Created cards simply could not be implemented in a physical card game. The same effect could be achieved physically with extra decks. But even then a physical deck has implications, such as finite size and shifting probabilities, that a digital game doesn't. Hearthstone's most recent expansion introduced players to "Spare Parts". These cards are created during gameplay, and although not very powerful, they are insanely fun. They've brought about new board states, interesting strategies and innovative deck building. But by far the most note-worthy use of this mechanic is the Priest card "Thoughtsteal". Thoughtsteal grants the priest player 2 cards copied from their opponents deck. It offers card advantage, information and complicated sequencing all in one simple interaction. The best part though, is it's an interaction unique to digital card games.

High Degree of RNG

Hearthstone features many mechanics and interactions that are reliant on randomness. The hearthstone team believes that this randomness is crucial in creating fun story-worthy gameplay experiences. The randomness also adds another level of skill to making the correct play. Being prepared for all possible outcomes takes experience, intelligence and foresight. Many RNG-based mechanics that take place in Hearthstone would be down-right tedious to calculate in a physical game. Rolling dice, flipping coins, or shuffling cards would become a long and arduous process. But because of Hearthstone's digital medium it's able to quickly and effectively compute random outcomes. With the power of a random number generator Hearthstone can create elaborate and skill-intensive board states. It can also create hilarious scenarios that are worth recording and talking about. The high degree of RNG positively adds to the overall experience and it's made possible by the digital nature of the game.

Automation

There are many aspects and interactions in Hearthstone that are incredibly complex. These interactions include turn phases, resource tracking and simultaneous card effects. Yet, despite all of these complex rules, Hearthstone is seen as a fairly simple game. This is because of automation. Automation is the implementation of complicated interactions that Hearthstone handles automatically. Implementing these complex rules in a physical version would likely require a judge, but Hearthstone is able to automatically resolve these issues for players. Automation also allows other game systems to function cleanly. Effects that would require a deck reshuffling in a physical game can happen quickly and without delay. Timed turns can be implemented without the need for some external turn tracking system. The list goes on and on, but what's important is that Hearthstone has used it's digital medium to it's advantage. The Hearthstone team designed the game with the platform in mind, playing off it's strengths. Ultimately, after several iterations, we're left with an innovative and powerful experience.

The Constraints of a Digital Card Game

Games that are designed well explore a medium's design space. Games that are designed exceptionally turn a medium's weaknesses into strengths. Hearthstone is the latter. It expertly crafts the limitations of the digital medium into it's strengths. It turns these constraints into powerful gameplay mechanics . And when that's not possible, it designs around them. Hearthstone is a game that is extremely self-aware. It dodges pitfalls that trap other digital card games, and even more than that, it hides these constraints in compelling gameplay.

No Discard Pile

Most card games feature a discard pile. It's a necessity in physical games, the cards need somewhere to go when they're not in play. It also opens up a lot of potential design space. It's another game location that can be interacted with, thus adding an extra layer to depth of play. However, when imagining a discard pile on a digital platform, one also has to imagine an intuitive way of interacting with it. Because of the limited resolution of mobile devices, a simple UI for discard pile browsing is all but impossible. A complicated UI coupled with the limited board space means a discard pile is a heavy investment. Hearthstone made the tough decision to omit an intractable discard and much to it's overall success.

Server Response Time

Hearthstone is a game intended to be played online against real opponents. However, several issues can arise because these opponents are not at the same table. It can take a long time for information to get from one player to another. This makes syncing actions, action responses and turn times difficult to implement. Hearthstone's basic game design understands these constraints and simply designs around them. In Hearthstone, your turn is your own. There are no responses that can interrupt it and no decisions to be made by the other player. The server may respond to your actions but it will never involve the other player. Issues arising from network latency are a severe constraint to any online game. Hearthstone simply accepts these constraints and tries to create an engaging experience around them.

Attacker Selected Targets

During combat the attacker selects both the attacking minion and it's target. This is in stark contrast to other card games such as Magic where combat is a very back-and-forth affair. The attacker-chooses model is used in Hearthstone to eliminate the need for opponent responses. Instead of a multi-phased combat system the attacker is the only one to make the decisions. Automated effects and responses are handled on the server so the attackers turn never needs to be interrupted. Like other constraints Hearthstone has come up with interesting ways to make this interaction feel different. Mechanics like Stealth (Minion cannot be attacked) and Taunt (Minion must be attacked first) were created as a result of attacker-chooses targeting. This combat system is something that makes Hearthstone different, intuitive and engaging. But most importantly, it eliminates the need for back-and-forth responses during combat. The end result is fun combat that doesn't open itself up to long waits or server collisions.

Secrets

The ability to respond to opponent's actions is a big part of physical card games. In games like Magic this gives the other player the chance to pull combat tricks, counter spells and be generally tricky. But this system cannot be converted to a digital medium without being incredibly cumbersome. In physical card games all that's needed to continue from these response segments is a verbal "Okay". In a digital game that same process takes the server contacting the other play, allowing a set amount of response time, and then communicating that response back. Although not a considerably long process, if this happens multiple times per turn, it quickly becomes a drag. In Hearthstone instead of requiring player input, the team simply designed Secret cards. Secrets are spells you cast on your turn that are triggered by opponents actions on their turn. Essentially, it's an automation to the action response system in other card games. When a player casts a secret it's information is put on the server. That way when a player commits an action that procs the secret it's just the server responding not the other player. Secrets not only avoid opponent response systems, they also add depth to the game. When a secret is cast, the event but not the card is known to both players. Knowing what secret your opponents deck plays and playing around it is one of the hardest parts of the game. Secrets turn the pit-falls of an opponent-based response system into one of the deepest and hardest parts of Hearthstone.