Over the last year, the roguelike has become the it-genre, particularly for independent developers. While debate remains over what constitutes a roguelike or whether the term should even be used, there's no argument around the fact that both developers and players have come to love these games for their endless, procedural challenges.

This year's best student game in the Independent Games Festival was Risk of Rain; Klei Entertainment sold over a million copies of Don't Starve last year. These are just two obvious success stories that owe a lot to the appeal of roguelike mechanics.

Tanya X. Short of Kitfox Games (Shattered Planet) succinctly captures this appeal: "As a designer, and as a player, I love procedurally generated, system-driven games because I'm curious."

That hook has lead more and more to explore the boundaries of roguelike game design. "I think success breeds success," says Don't Starve lead Kevin Forbes. "There have been a couple of really good games in the past few years that serve both as an introduction for players, and as inspiration for developers."

Daniel Cook, developer at Spry Fox (Road Not Taken) explains another key element of the genre -- its longevity. "I've been playing NetHack for well over 20 years. It is very much a hobby for me. The long-term variability, depth of mastery, and richness of evergreen surprising moments are an anomaly in this era of disposable movie games," he says. In fact, the roguelike -- from its history to its design space -- is so fruitful that "there's a book that could be written on this topic," he says.

"When some journalist / grad student / pundit asks 'What is the culturally relevant future of the game industry?' one loud and clear answer should be 'roguelikes,'" says Cook.

Why do players and developers love them? 

The roguelike has caught on not just with developers, but also with players. Why is that? 100 Rogues developer Keith Burgun puts it down to a renaissance of players looking for games that offer rich play experiences -- which we can also see in the surge of popularity of everything from Minecraft to European board games, he suggests.

"I think people are just slowly, but surely, getting a tiny bit more ground about 'what games are.'  They are realizing that games are fundamentally way more than just a Universal Studios theme park ride."

He continues, "I think they're starting to realize how important gameplay -- quality interactions -- are, and that's causing more and more of them to look in places that they wouldn't have before."

Short notes that players are attracted not to the idea of the "roguelike" per se, but the experiences these games afford to them: "People don't play first person shooters because they like the word FPS; people play FPSes because they enjoy shooting guns as an immersive experience."

"What I love as a player is that I'm constantly running into new situations that I want to share with my friends," Cook says. Short agrees: "Their value tends to be in providing the maximum possible array of outcomes... i.e. satisfying novelty as long as possible, with the minimum number of elements."

Burgun notes that this novelty can speak to gamers in a very basic way, with roguelikes offering "so much stuff in one package that surely something in there, you're going to enjoy."

"You can be surprised by something new every time you play. You can challenge yourself to learn about and master complex systems," Forbes says. "I think that a lot of players really appreciate being able to direct their own experience, and emergent gameplay lets things happen that keep the experience fresh. There's a level of replayability inherent to the genre that's sorely missing these days."

The roguelike allows for "unique, surreal and wonderful collisions between player agency and complex systems," says Cook, a mode of expression that is "unique to games."

Forbes continues this thought: "I've always found it odd we game designers have such an exciting, unique medium to work with, but so often waste its potential trying to emulate film."

It's the potential for surprise that can excite both the player and the developer, Short says. "As a player, I feel like any given mechanic or system can reliably be pushed to its limits, as a challenge and as a strategic tool. And as a designer, it's incredibly satisfying to watch players use your systems to come up with new strategies you didn't think of."

Developer appeal goes further than that

But its appeal for developers extends well beyond that: Roguelikes provide an exciting creative space, certainly, but the genre also allows today's smaller teams to stretch their resources.

"I think every designer now has to ask themselves, at the start of any game project these days, 'Is there any way I can procedurally generate any of my content without the quality suffering enormously?' Any answers to the affirmative must be taken seriously. The value-to-cost ratio is just too high," Short says.

Cook puts it more succinctly: "One- or two-person teams can't afford to make 100 hours of sexy 3D-storytime. But they can make 100 hours of roguelike bliss."

The savings is not simply based on the fact that content is generated procedurally and thus, in some sense, free -- the thinking required to create games like these also insures design changes won't result in costly rework, says Cook. "With static levels, a change to your core mechanics could result in months of rework," Cook says. "Regenerating levels after a change to your game mechanics is a trivial exercise. Content becomes amenable to cheap refactoring."

That flexibility also results in a fundamentally different kind of gameplay, says Defender's Quest developer Lars Doucet. "In most other games, you can always reset, or reload, and use your knowledge of the future (or of unchanging levels) to march your way forward. Most video games are like karate katas that you practice over and over again. With roguelikes and procedural death labyrinths, it's an actual fight on the streets -- you don't know what's coming at you, and you have to improvise and think on your feet."

This procedural flexibility, in concert with mechanics like permadeth that the genre has popularized, "opens up the possibility for single-player video games to actually be contests -- to be competitive -- to be a thing you can win and lose," notes Burgun.

Anyone who has made a game has first-hand experience with gameplay systems that never took off, and games that never delivered the promise of their initial prototypes. Roguelikes are also insurance against facing that scenario, argues Cook.

"There's nothing worse than finding yourself six months into production only to discover that the mechanics that seemed convincing enough in test tube of preproduction are in fact shallow and boring," he says. "By prototyping with procedural levels, you are forced to make your core mechanics robust in the face of really bizarre scenarios. This robustness tends to yield playspaces that deal with all sorts of abuse in terms of future expansions or balancing issues while still remaining fun."

He zooms out: "On a higher conceptual level, roguelikes pose a strong aesthetic stance. They say: What if our game was treated like code? With simple modular objects; with systems of interaction; with a certain physics to the world."

This allows for better collaborations -- a particular must for small teams -- argues Short. "I think roguelike design is extremely programmer-friendly… which means indie-friendly, since most indie companies are at least 50 percent programmers. Roguelikes are puzzles to be solved, and programmers (and technical designers) dig puzzles."

This leads to games that are well defined by their own gaminess. "They aren't shy about being games with game verbs and abstract game-like rules," says Cook. "Sure, that fluffy writing and art stuff can improve a roguelike, but the core fun is the logic of the systems. Systems beyond spreadsheets," adds Short.

All of the above cascades into a game that is primed for constant evolution -- which is increasingly crucial as game developers strive to keep players interested in a game past an initial purchase, and to build communities. That's another secret to their appeal for developers. 

"They're perfect for constant evolution. Every additional item isn't a new episode – it's a new world of possibility," says Short. "Now that it's common knowledge that you can sell your initial game, and keep working on it, potentially forever… it's an indie dream come true."

"With a roguelike, you can add in 2,000 new objects and the whole system adapts with the press of a button. It is still hard work, of course, but here's a style of game that thrives on never being finished," says Cook.

"There's a lifetime of potential expansions you could pour into a roguelike. How wonderful would it be to have a community playing a game 30 years from now that they still consider fresh and exciting?"

It goes further than that, however, says Short. "The value of proc-gen isn't just in replayability; players comparing stories and strategies of how they survived a roguelike is part word-of-mouth marketing and part player generated content! Normally, you don't get that kind of community-building virality except in multiplayer."

That has already driven success for Don't Starve. "Social media and the whole Let's Play scene are providing a platform for players to present their play as performance, which works really well with procedural and emergent gameplay. It's also free advertising, which is hard to resist," Forbes says. 

Flexibility, adaptability, and the future

Roguelike elements are fast becoming part of the fabric of gaming -- even creeping into triple-A titles. "I think the fact that a game like Demon's Souls has mass appeal means that players are warming to some of the ideas," says Forbes.

Even players with much more casual tastes are also prepped to appreciate the fruits of the genre, Short argues: "Games like Candy Crush demand mastery and improvisation. It won't be long before a roguelike takes the mainstream by storm."

The genre is highly adaptable, as Doucet points out, which also bodes well for its success. "I can start one of those up, have a unique and interesting experience in 15 minutes, get my butt kicked, and try again. This is very important when you're an adult and have less time. Within those parameters, it's the perfect genre for me."

Cook suggests that the "roguelike" is a framework to build a game on. He sees Edmund McMillen's The Binding of Isaac as a great example of how melding roguelike concepts to ideas taken from other games can still lead to a coherent and compelling whole.

"What I find exciting is how people are now breeding these wild chimeras out of a half dozen different genres and gluing it all together with roguelike architectures. The architectural element, how the various individual design patterns fit together into a robust whole, is something that is worth more attention," Cook says.

Its changeability opens up thematic possibilities, too. "I want to use the genre as a way to explore real-life conditions. In real life, you can't hit the reset button and use knowledge of the future to subvert the challenges in front of you," says Doucet. In his spare time, he's been working on Tourette's Quest, a game that explores his own personal challenges. Thanks to the genre's strengths, he says, "I can make a game that's fundamentally about risk management and learning to embrace the physical limitations of a disability."

Despite the potential of the genre, Cook also worries that it could become played out. It's a danger of any genre that comes into fashion. "There's an opportunity to make better games by smaller teams. The risk is that they just copy tired patterns and run the concept into the ground."

Looking ahead...

This article has consciously sidestepped the issue of orthodoxy that has been such a piece of the discussion around the roguelike genre. Forbes' take on his own game exemplifies this conversation well: "Don't Starve uses permadeath, procedural world generation, and discoverable rules-based systems. It's quite a bit less directed than a classical roguelike, and in fact I would consider it more roguelike-inspired than an actual example of the genre."

Both Doucet and Short have covered this topic in depth, if you're interested in learning more. Burgun, in fact, doesn't see the value of considering it a genre rather than a set of mechanics to experiment with: "Probably, the genre should be destroyed, and actually I'd argue it maybe already has been." The goal of this article is concentrating on what core roguelike mechanics make possible for game developers.

It's clear that, genre or not, the design elements that make these games compelling are both identifiable and useable in a wide variety of contexts; they are now part of the lexicon of game design.

Our interviewees paint a bright future for games which take inspiration from these mechanics, and it isn't purely because they're compelling to play: there are also production and promotional reasons that make them extremely attractive. That adds up to a recipe for an enduring legacy.