Shortly after it was released in 2014, Dave Kosak, current Lead Mission Designer for Hearthstone began experimenting with puzzles. “The idea was to post some sort of board situation and see if you could figure out how to defeat your opponent that turn,” a reference to a specific type of problem that what would eventually become a Lethal Puzzle – part of Puzzle Labs, the new single-player component of Hearhtstone’s latest expansion The Boomsday Project. The idea of creating scenarios for players to solve or card their way out of, has been sitting with the development team at Blizzard for some time now.

“A couple years ago, we tried to make a puzzle Tavern Brawl as a special event,” Dave adds. “And it was enjoyable to play, but it needed a little bit of UI support. It really needed some extra razzle dazzle to help feel like, ‘What if I want to start a puzzle, and pick it up again later? What if I wanted to restart my turn quickly?’” This internal feedback may have shelved the idea, but only from an implementation and technical perspective. Creating Hearthstone puzzles as it turned out, in a similar fashion to old-school chess problems, was indeed possible and enjoyable. It just needed the right theme.


“When we were preparing for The Boomsday Project, we knew this was the perfect opportunity to do puzzles,” Dave explains. “It's an expansion about science and experimenting with things, and a lot of the puzzle mechanics really do feel like science problems. Like trying to create the perfect chain reaction or solve this mystery.” And so, from there the initial idea and testing that had been carried out for a number of years at varying levels was now brought to the fore.

But before Puzzle Labs would become a fully playable part of Hearthstone, the team at Blizzard had to solve a few puzzles of its own. Being able to reset the board quickly, make it so puzzles could be tackled one after another without going through load screen after load screen, and being able to pick things up where you left off. It was a challenge that came together quickly – but then opened the door to an exciting new way to play Hearthstone. In creating puzzles, the mission team, responsible for the single-player component of each expansion, began working on several scenarios. But, it was also a case of everyone chipping in to put their own spin on the concept.


“We did reach out [to the team] because everybody was kind of excited about creating puzzles,” Dave tells me. “Our event team created some puzzles; our initial and final designers created some puzzles too. And we really fleshed out our puzzle roster that way.” The tricky part, as expected, was putting it all together. Having easy puzzles come first, but also ensuring that players experience a difficulty curve that not only ramps up the further they proceed – but surprises and excites them along the way. In the end deciding on what puzzle might have been more difficult than one but slightly less difficult than another, took considerable time and effort.

Tim Erskine, Senior Game Producer on the Hearthstone team notes that with Puzzle Labs, the testing itself took on a larger scope due to this focus. On not only introducing puzzles into an already established game but getting the feel just right. “The mission team who works on most of these puzzles, every day they become more familiar with the content - they get deeper into it, so it's really hard to take a step back,” Tim explains. “So, we did a lot of testing differently than we normally do. Throwing everyone at [Puzzle Labs] all at once, plus we asked different sections of people to look at it at different times. We always wanted to get a fresh pair of eyeballs on it and evaluate it from a new perspective.”


“We discovered what our final design team considers to be a challenging puzzle, might be too crazy for everyone else in the world,” Dave adds. “Getting that feedback from a wide group of different skill levels was really valuable to us.” One interesting bit of feedback born from testing Puzzle Labs was that the longer players spent on a puzzle, the more satisfying they felt after completing it. A fact that lent itself to the design of increasingly challenging scenarios and puzzles, where leaving players stumped or stuck wasn’t necessarily a bad thing.

So then, by this point you may be wondering what a puzzle game within Hearthstone looks like. From a pure design perspective, the answer is simple and straightforward. Broken up into four categories, players need to solve a scenario within a single turn using the tools – and cards – at their disposal. Lethal puzzles are the easiest to understand, as all you need to do there is defeat your opponent. Mirror puzzles require you to match your opponents’ side of the board exactly, hence the name. Board Clear tasks you with clearing the board of all minions, and Survival required you to heal and shore up defences to survive an onslaught.


In terms of the development of Puzzle Labs, Lethal Puzzles came first followed by Board Clear. Two styles of play that are already well established in Hearthstone. “Where the team really outdid themselves was the new types,” Dave adds. “Mirror was a brand-new puzzle type, because the objective isn't quite as obvious. If you have a wounded minion on the other side of the board, you could destroy it to get rid of it, you could heal it up to full health and create a copy of it, you can create a copy of it and then wound your copy of it to make the health match.” The combinations were endless and showcased that Puzzle Labs strength lie in its source – the simple to learn yet seemingly infinitely complex core Hearthstone experience.

Survival on the other hand proved to be the most challenging and the type that saw the most iterative work carried out on. Originally Survival puzzles would take several turns to complete, upping the complexity by posing a situation whereby the player had, for example, four turns to survive. “It didn't feel as clean or as elegant as some of the other puzzles,” Dave recalls. “Ultimately we decided the puzzles feel best when they took place over a single turn and there's a discrete solution.” From there the very concept of Survival changed, where the puzzles were redesigned from multi-turn problems to single-turn scenarios where players had to figure out ways to heal their hero to full to survive an impending attack.


What makes all of these puzzles exciting is their context within the greater meta of Hearthstone. Where hundreds of cards, each with their own traits and stats, spells of varying outcome, and heroes with different strengths and weaknesses come into play. Handy tool-tips provide explanations for all the above, and in keeping their use limited to a specific scenario, Puzzle Labs has the side-effect of teaching players about the deeper mechanics of strategies and potential creativity in Hearthstone. Certain puzzles also have more than one solution.

“I'd like to believe that by solving the puzzles, we're making you a better Hearthstone player because you start to think about the cards differently and you think about their potential differently,” Dave confirms. “It certainly wasn't necessarily one of our design goals. We didn't intend it as a teaching tool, but a great benefit is that you start to learn about these different combos and different things to do and hopefully gain more of an appreciation for Hearthstone's mechanics.”