Spelunky (Boss Fight Books, #11) (original) (raw)
22 reviews5 followers
Read it through from beginning to end in one sitting, something I haven't done in about 15 years. Of course very much dependent on my current obsession with the game, but Yu very clearly and interestingly goes into the depths of his creative process. Hard to put down.
Author 30 books384 followers
Such a great read!
Spelunky, if you haven't played it, is a roguelike platformer. Which means it's kinda like crossing The Legend of Zelda with Super Mario Bros. with D&D.
The gimmick is that the game randomly generates the levels. Which sounds like it totally shouldn't work, but it totally does. Through some clever coding, each level being made of tiles with certain rules, levels are always generated in such a way that the player can navigate from beginning to end using only movements that are built in to the game. You won't start in a walled-off room and just be screwed. It's clever that way.
Now, when playing, the randomness didn't impress me much. Because I'm not a programmer, and also because I like to use the phrase "That don't impress me much" whenever I can. Any chance I get to break into a Shania Twain song, I takes. But reading this book helped me understand the decision to make the levels randomly-generated wasn't just a hook. It was part of a whole philosophy of gameplay constructed by Derek Yu.
If you have any interest in gaming, game design, or the philosophy of fun, this is the book you need to read, the best book that'll come out on the topics in 2016, I promise you.
If you don't, I still recommend reading this book. There's a lot in here about turning a hobby into a career, how important it is to actually finish creative projects, and even some project management stuff from a surprising and really excellent source.
If you haven't played the game, I recommend that too.
I'll admit, I kinda hated it at first. It was so hard. And the objectives weren't clear to me. And it seemed so luck-based. The random generations could mean that you had an easy area to clear, or a very difficult one. That didn't seem fair to me.
But then I played it with my brother. And that was so much fun. When it was fun to die in the game, when we challenged each other to piss off berserk shopkeepers, when my brother showed me how to unlock some of the game's secrets, when we tested the boundaries of the game and each other, that's when I saw the real joy of the game. That's when I saw that it's not about luck. It's about playing often enough that your skill level allows you to navigate through any iteration of the terrain. The mastery is about skill-building, not treasure hunting or finishing levels. It's a really different idea of mastery, and I have a new appreciation for it after reading this book.
The game is also a really good answer to something that plagues modern games, the easy availability of walkthroughs. A walkthrough is nice when you're stuck, but it can be a crutch. And not the kind of crutch you use when your leg is hurt. The kind you use to reach across the coffee table and bring a bowl of Funyuns closer to your spot on the couch.
If no two levels look the same, what good would a walkthrough be?
So I'll admit, I needed a little guidance. I needed an experienced player to show me how things worked. To explain the rules to me a bit. What you can and can't get away with. And then? It was so fun. It was a blast. It took me back to the days when I played games with my brother all the time.
If you've played the game, read the book. Even if you didn't like the game, I think you'll like this book. If you haven't played the game, play a little or watch a little online, and then read the book. It's a really cool book.
Also, if you can get your hands on the print, do it. Boss Fight puts out some really kickass physical books. Totally worth the extra layout.
38 reviews2 followers
it's called Spelunky, what am I supposed to do, not rate it five stars?
Author 5 books21 followers
This book is a terrific window into the creative process of a successful indie game developer. I recommend it to anyone who is fascinated by how professionals at the top of a field operate, regardless of the field. It is especially interesting of course to artists and other creative fields because of Yu's methodology, and to game developers and players because of his medium.
Yu is primarily a designer and artist. You don't need to know anything about programming or game graphics to read this book, and they aren't discussed at all. You also don't need to know anything about video games--he explains everything clearly and assumes no background knowledge. And you need not like or have played Spelunky, although fans of the game will certainly enjoy the book especially.
The writing is fantastic. It is simple and clear, yet also comprehensive and dense with wisdom. Yu has a very mature perspective on his own work. He dives into balanced criticism of his work and adds his own. He also has an admirable tone of optimism and praises several other luminaries in the field (many of whom have strong, difficult personalities, so it is all the more impressive that he focuses on the positive).
I've written a lot about games, myself. This is a book I wish I had written, or had the ability and experience to write. It took me a few hours to read it cover to cover, and I look forward to many re-reads. There's a lot in there to revisit and ponder.
[A dark note not evident to readers outside the industry is that Holowka, Yu's business partner and internet friend in the first chapter, committed suicide in 2019. Holowka is widely believed to have been both a victim and perpetrator of physical and sexual abuse, including using his position as a feted indie developer to harass and abuse women. I think all of this either hadn't happened yet or was unknown to Yu in 2016, when he wrote this book. Despite Yu's great games and great writing, I'd like to note that the indie games community is not immune to the evils present in the rest of the world; the great moments and contributions are indeed as strong as he says, but there are lows as well.]
369 reviews12 followers
”The creative mind is like a big pile of jigsaw puzzle pieces. Some pieces were made by other people—inspirational words of advice, an intriguing screenshot from a game you've never heard of, a haunting melody—and some are gained through life experiences. Some pieces are already connected, either because they came that way or because while you were walking down the street or taking a shower they somehow found each other. Sometimes a single piece is missing, and once that piece is uncovered, two other pieces from different ends of the pile can finally be connected.
It's important to accumulate many, many jigsaw pieces, since the more you have available, the more things you can build. But eventually you have to sit down and start sifting through the pieces to put them all together. This is the ‘work’ part of creation. It can often be frustrating, like when two pieces seem like they should fit but don't. Sometimes you know that there's a perfect piece around but you're not sure where it is. Is it even in your head? But like any challenging task with a noble purpose, the frustration also gives way to joy, elation, and ultimately satisfaction when you've finished a big part of a new puzzle.””I've tried programming a game engine from scratch before, surrounding myself with books like Tricks of the Game-Programming Gurus in an effort to ‘make games the right way,’ but when days of work yield as much as I could make in Game Maker in a few minutes, it's hard to stay motivated. At the beginning of each semester at Berkeley I had the same sort of naive gumption, buying pristine notebooks and attentively jotting down everything the professors said, only to succumb to ennui a week later, my notes devolving into irreverent doodles. Post-school, however, I accepted that I wasn't cut out for academia and programming theory. I no more wanted to program my own game engine than I wanted to fashion my own paintbrushes. This important realization meant I could stop wasting my time trying to be something I wasn't. Instead of being embarrassed about not being a ‘real programmer’ using ‘real programming languages,’ I vowed to make games whichever way felt good to me.”
“The Chain's final purpose is to provide permanent features to a randomized landscape. Although randomization gives Spelunky and roguelikes their longevity and makes each playthrough feel unique, it's what stays the same from run to run that makes the world feel real. But without the randomization, playing the game enough times to figure out the Chain would be much more repetitive. The permanence of the Chain and the randomization of the world work in tandem to give you a greater appreciation of the other.”
960 reviews98 followers
Pretty good. I read this on Kindle Cloud E-Reader! Dot com. Truly, the future is here. I already feel ripped off though that I paid $5
12 reviews
Great write-up of the trials and tribulations of developing a roguelike sensation by mastermind Derek Yu. While very interesting and full of fascinating tidbits about how Spelunky came to be, reading this book had an unexpected side effect: I really don't feel like playing Spelunky now.
Derek Yu is not just a great game designer but also a great writer. Spelunky is entertaining book full of interesting little stories from game development and designing advices. If you are interested in game development, you should read it.
790 reviews22 followers
I have enjoyed many of the books in the Boss Fight Books series. They're each unique in their own way, but this is the only one (that I know of) written by the creator of the game. It was fascinating to read Yu's thought process as he chipped away at various ideas and finally ended up at Spelunky.
Yu mentions in the final chapter that his game came about at the right time for an indie resurgence, but it's especially interesting reading this book at the same time as Super Power, Spoony Bards, and Silverware: The Super Nintendo Entertainment System, a history of the SNES. That is a period where, on consoles, it was more or less impossible to be a bedroom developer because of the way Nintendo controlled the market. So this book also functions as somewhat of a history of the early days of the indie video game market.
Primarily, though, this book reads somewhat like Jordan Mechner's journals for Karateka and Prince of Persia. It's an autobiographical take of Yu and the decisions that made Spelunky what it is. Although I think any videogame enthusiast can enjoy this book, I enjoyed it a bit more as a developer myself (mostly not of video games, although I have taken video development courses) because I understood a lot of the constraints that Yu mentioned.
humble-or-story-bundle video-games
518 reviews16 followers
I'd wanted to read this for a long time, even though I am borderline incompetent at Spelunky the game; every tidbit I'd read about how it was made was fascinating. And I like the approach Yu has taken here; the way he works seems very informed by his personality and the way he approaches life in general, so of course those should be in the book as well. It's a very approachable, likable book, and although I'm not planning to make a game myself I feel like it's a pretty good shot of inspiration and maybe even some tips for someone who is.
14 reviews6 followers
A quick, delightful read. I'm glad I read this after watching Indie Game: the movie, because most of the main people in that movie make an appearance in this book in one way or another.
I particularly like his idea of finishing projects as being it's own skill. He mentioned influences and origins of different popular movies that I didn't know about and how some of these things made their way into his own games.
Highly recommended for anyone with an interest in indie game development.
342 reviews6 followers
Super interesting book about the development of the indie game Spelunky, written by the game's main developer. I really liked it! Seeing the backbone of the random generation inherent in the game as well was really interesting, and Yu's thoughts on the process of game development and (by proxy) navigating being a creator in general was very cool.
4/5 stars
Author 40 books71 followers
Un excelente ensayo personal sobre la creación de Spelunky. El creador del juego nos cuenta el desarrollo del mismo así como los mecanismos que lo definen (código, mitología, mitología, arte previo). Un fabuloso ensayo de creación, estructura artística y disciplina. Muy recomendado para todos aquellos que deseen asomarse por la cabeza de un creador de videojuegos.
59 reviews1 follower
Really fun and easy read. Hearing the creator detail his design choices is really fascinating. Yu also speaks to the direction game design is going in and how it shapes the expectations of video game players as a whole. Hopefully the challenging and explorative design of Spelunky never dies.
Un libro realmente interesante y disfrutable si te gusta Spelunky, el boom indie de XBLA o el desarrollo de videojuegos. Si por el contrario no conoces nada del tema o como mínimo del juego pienso que es mejor abstenerse.
Se diferencia de los demás de la serie puesto que está escrito por la mente pensante detrás del proyecto, Derek Yu, lo que le otorga ciertos tintes autobiográficos que hacen la lectura mucho más agradecida.
62 reviews2 followers
A nice little book about a great little game.
But it seems to be written for die-hard fans of the game, and going into all the minutiae of the development cycle was little too much for me. I hope one day Derek Yu will come up with a more general book about game development and I'll read that one too gladly.
48 reviews
I contributed to Boss Fight Books' Kickstarter campaign pretty much solely for this book. While a bunch of them looked interesting, at the time of the campaign I was subject to the austerity inherent in founding a startup. There were two reasons why I couldn't pass up the Spelunky book, though (above the fact that the digital copy was inexpensive): 1) a couple of years ago, I played a lot of Spelunky -- a lot of Spelunky; 2) this is one of the few (only?) books in the series written by the subject's creator.
The book covers the genesis of Spelunky Classic (née Spelunky): a freeware 2D platformer/dungeon crawl/rogue-like coded by just one dude (author Derek Yu) in GameMaker. It gives you the designer's perspective on things like the algorithms the game uses to randomly generate levels as well as how simple, logically consistent rules layered atop each other yield complex behaviors (enemies, game physics, etc.). Derek also recounts the (at-the-time) nascent indie developer community, the inspiration behind the game as a whole, and the difference between working by yourself on a small game versus working with a couple other people on a (slightly) less small game. It talks about working with Microsoft on the remake for XBLA, as well as pulling in programming & music collaborators, and its eventual port to PSN and Steam. It closes by discussing some of the secrets and easter eggs hidden in the remake and their discovery over the ensuing years after its release.
The writing style is pretty solid: conversational rather than dryly technical. There aren't many typographical errors; I think I only caught one, and that was in the notes addendum. A+++ would buy from again.
1,018 reviews70 followers
Spelunky (2016) by Derek Yu is all about the creation of the game Spelunky. It’s a surprisingly interesting book for anyone interested in how people create.
Derek Yu loved games form a young age and really wanted to create them. He studied at UC Berkeley but didn’t really enjoy coding. Interesting he used GameMaker for the first version Spelunky. Spelunky is a procedurally generated platform game where an Indiana Jones type explores a mine and other levels. The book describes how Yu created the levels so they could be completed. He also writes about porting the game to the Xbox and to Steam.
Spelunky the book is well worth a read for any fans of the game or people interested in how two people can create a hugely successful game. Yu writes well and the book is a fun, quick read.
1 review13 followers
I really enjoyed Derek's discussion about the development and the reasoning behind many of his decisions. However, as the book went along it seemed more and more like writing this book was more of a burden than a pleasure. I greatly appreciate that he took the time out of his life to bring the development of this essential game to life and I look forward to what he makes next! (Spelunk 2 please)
1 review1 follower
A super interesting window into the development process of one of the best designed games in the last decade.
76 reviews6 followers
A perfectly cromulent book. Kind of comes off like a GDC talk that got turned into a book - a good but somewhat surface dive into the development of Spelunky that also serves as a sort of personal manifesto for Derek Yu's own design philosophy. It's fun to read because Spelunky is just such a fun game to think about, so having the creator guide you through aspects of it and how it came to be is a nice little treat. Definitely made me want to stop reading at several points just to fire up the game again and check out something he'd been discussing.
IMO the games he discusses as the influence on not only Spelunky but his design philosophy in general aren't really that surprising - your _Legend of Zelda_s. your Hack, and of course Rogue, games heavy on discovery and unique-feeling interactions that come about from the systems working together. While stories about how these games included like, punishments for overeating are fun to read about, it's definitely Derek's story about the time he saved a troll from a pit just to see what would happen that had me nodding my head. That's the good shit, man. As much as I do enjoy games with more limited interactions and less like, system discoverability, reading about things like this, about pushing against a game and seeing how it responds and how it can surprise you, really gets into what the strength of this medium can be. I remember on an early episode of Remap Radio, they were talking about a game and one of the hosts, Ren, said something like "so this is how you tell stories about this game" and it really stuck with me. Not every game works like that, but the ones that do really feel special in some way. While I'm not really here to review the hit video game Spelunky I think you can see how he managed to capture a good deal of that in the game he made.
There's also something interesting in the way the influence evolves too. When he was making the first Zelda game, Shigeru Miyamoto was basing it off of how, as a kid, he would explore the countryside near his home and the vivid memory he has of the time he found a cave and the curiosity he had about what was in it. He talks about wanting to instill that feeling the players of the game. Derek talk about playin the original Zelda in a similar way - that it was an after school activity he enjoyed doing, that sense of discovery he got from it, and it made a huge impression on him. And now here he is later, making a game in part based on the feeling he got from a game about exploring a fictional world based on exploring the real world. No real point here to put a cap on this thought, just curious how the influence evolved over time!
Probably my favorite part was Derek talking about "the chain," the hidden difficulty path that he put in the game, and his general philosophy around difficulty in games. There's a kind of "it's difficult but it's very fair to you, since the entire world follows the same rules you do" thing to Spelunky that certainly takes some getting used to, but once you do, well, the game becomes something you can have fun telling stories about, mostly about the hilarious deaths you're suffering. So you find the fun, but then, the game's got its own other secret level of difficulty that you can add to it optionally. The fact that he added it in and didn't hint anything about it is a lot of fun too, and while I'm sad I wasn't there to be part of the like initial community that discovered it, even knowing what the chain is and how to do it, it's still a level of difficulty that I'm not capable of achieving. But every time I get that Udjat Eye.... I wonder if, maybe...
The story he told about the initial playtester who left a (rude) message about how the game was too difficult, but then would continue to leave (rude) messages where he'd mention that he was still playing it and getting better and further, was really interesting too. And while the player kept asking for an easy mode, Derek didn't want to add one and felt vindicated as the guy kept coming back and improving. Which I think also says a lot about the difficulty he worked to create and how well he managed to walk a pretty thin line between "too difficult, makes me want to quit" and "too easy, so the repetition isn't that fun." Lord knows I haven't completed a run, but I still keep feeling the draw to return!
Anyways yeah it's a fine book and it's a super breeze to get through. It's probably not that surprising that the creator of the game manages to walk through what he thinks is so good about it, but he does it in such a compelling way. It seems like it would be fun to just ask him questions about various things and he'd have some fun answers for how it all came together. I probably am gonna go check out and see if there's a GDC talk now actually. I just _Spelunky_-pilled myself and only have myself to blame.
34 reviews3 followers
Spelunky is an amazing game.
Personally I’m not a huge fan of actually playing it, because I suck and die all the time. However, I still fire it up from time to time and play for half an hour before I get frustrated again.
I keep coming back to this game even though I know that I’ll get my ass kicked yet again. This is quite rare for me. Usually I’ll just move on if a game is too hard. I’m that kind of gamer, I guess. Apart from Super Meat Boy, Spelunky is the only game that keep pulling me back for more punishment. Why? Simply because its mechanics are amazingly well designed (oh, and it has an awesome soundtrack).
The book is written by the author of the game, Derek Yu. As luck would have it, he’s a great writer. Much better than I had expected from a video game developer.
I really like how the book has two sides to it: It tells the story about how Spelunky was developed and how it evolved as a game. But it also goes into quite a bit of depth about details of the game design. All the little dilemmas and details that you probably don’t even think about when playing the finished game.
Excellent games like Spelunky can be so deceptive. I still remember the first time I saw it. I loved the soundtrack immediately, but was unimpressed by the game mechanics. It looked so simple! What was all the fuss about?
Then, it slowly became apparent to me that although it is a simple game, it is so extremely well designed that it grows on you in a very special way.
The satisfaction of learning to control the basic weapon, the whip. Like…really control it. There’s a lot more finesse to this than just pressing the button.
The joy of seeing NPCs interact with each other in completely unexpected ways. The classic example of this is the boomerang man in the jungle (forgot his actual name) who loses his boomerang and steals a new one in a nearby shop, angering the shopkeeper and getting shot to pieces. Because, well, he was missing his boomerang and he is programmed to pick up the first one he comes across. Which in this case happened to be in a shop.
It’s a small detail, but it just contributes to a wonderful sense of coherence in the game that is probably one of the main reasons I love it so much. At some weird level, it actually feels authentic.
I mention these things because even though I’d noticed them from the game itself, the book gave me a much deeper appreciation of the work behind it. The reasoning behind why things behave the way they do. Also, it was really interesting to learn about a few of the more technical details that I’d never considered.
Note that (unsurprisingly) the book contains some pretty major spoilers about the game. Casual players may not even notice these secrets though, so this is mostly relevant if you expect to really geek out and pour hundreds of hours into the game to really master it.
Finally, this is a short and easy read. Well written in an easy language, and not very long (notice that the font size is quite big).
Highly recommended for anyone with an interest in indie games, also if you’re not a developer.
Game design student and rogue-like lover, I never played Spelunky, not once. Of course I've heard about this game, a lot, I've seen many footages, I've had friends spending hours telling me about the hundreds of hours they spent on the game, how hard it is to get to the true last boss, all the little secrets that turn a "simple" game into emerging stories that can be shared with people.
This book's not only a report about some technical aspects of the game, or the process of indie game development in 2008, which it does really well and is really pleasant to read, given you've played a video game once in your life and aren't afraid with some low-level specific terms, it's also and above all a story about artistic creation, about human creation. Whether you like video games or not, whether you're creative or not, it doesn't really matter, as this book is about a person that went from creating a small thing for fun and sharing it with some people with no further intentions, to working hard day and night to release it on (the at the time) the best platform for independant games developer to reach the mainstream public. He saw this little project, that nobody was meant to see but himself, become one of the most successful indie game of its time, participating in the huge rise of indie games in the next years, and creating a vast community that still lasts today.
To conclude, I believe Derek Yu already has the best words:
"In the end, isn't that why we create things? Not just for the power of putting something into existence, but to connect with people and be part of the conversation that is human history. To have something that speaks for us when we're not speaking and even after we're gone."
41 reviews
A good book if you're interested in what goes into game development. Derek is not a writer, but he is in the unique position of having made one of the best ever games (the best, imo) but having the creative process been a relatively mundane event that you can easily learn from and iterate on. Derek formed his personal ethos about how to push yourself through the unhappy parts of programming in order to actually release a creative product. It's an interesting thing to think about, this marriage of creative work and engineering process that can end up producing something of real beauty. Derek talks a lot about how he views games, as these sets of rules and scaffolding, cobbled together, but with a driving engineering ethos behind it that can end up creating a little microcosm of how childhood exploration feels. It's pretty interesting.
I have two more of these Boss Fight Books things, about Katamari and Shadow of the Colossus. I think I'll find those a little more interesting because they involve people who don't usually make Medium posts about development anyway. There is something a little silly about the packaging, trying to make a sort of Criterion Collection for videogame behind-the-scenes.
118 reviews9 followers
If you've seen the NoClip documentary on Spelunky, you'll already know a lot of the story behind this game, but the overlap with this book is rather small—plenty more to learn here.
How the idea for Spelunky came about, and advice on how to find ideas in general. What it was like prototyping the first version. How the elements of the game came together, with detail on how the procedural level generation works. How the indie community received the game, and how the free game turned into start of development for the commercial XBox version, which was a much longer project than I had imagined. Lots of great insight into how to actually make sure you make progress and really release things instead of getting stuck with a project.
Why is there an eggplant in the cover? That's one of the secrets of Spelunky, covered in great detail. Overall an excellent book on an excellent game, written by the author of the game himself. I enjoyed reading this as much as Making of Prince of Persia, which had been my favorite gamedev book so far.
A Fascinating Look In Into My Favorite Game
As a fan of Spelunky, I've always loved the game's randomly generated levels and super charming music and art style while constantly being frustrated at its intense (but always fair) difficulty. Reading through this book gives an incredible insight into the triumph that this game has become in being able to balance all of those aspects while still showing the love and heart that Yu and the others involved put into the project.
Having first learned about the game from seeing its biggest secret, the solo eggplant run mention in the final section, this book shows just how much the passions of a team really can translate to the community that grows from their work and helps to make that piece feel like it has a life of its own.
I heartily recommend this book not only for fans of the game itself, but for an interesting look at a game design from the man who made one of the biggest indie darlings where you can rescue a dog with its tongue hanging out.
166 reviews
I deeply enjoyed this and devoured it in two sittings on the same day, only because I found the need to play Spelunky in between. I recognize a lot of accumulated wisdom here and also feel a considerable amount of shame, as Derek Yu and I have so much in common — except for this:
I’m obsessed with finishing as a skill. Over the years, I’ve realized that so many of the good things that have come my way are because I was able to finish what I started.
(from the section "Finishing a Game", which is itself a variation on an earlier blog post from Yu that I've re-read several times in the past.)
Really, that's the underlying message in this book, that comes back again and again. This little book is a must-read for aspirational game developers. Aside from such project management advice (which is probably the most important part), there's solid analysis of how creative ideas come together into concrete projects, and lots of well-thought-out consideration about gameplay.
biographical inspirational videogames
Author 3 books3 followers
One of the best books I've ever read about game design, hands down!
Turns out that not only is Derek Yu a wonderful game designer/developer, he's also a talented writer who manages to explain many of the thought processes that went into the development of the game. It has definitely given me ideas on approaches to certain things in my own games.
It's also given me a renewed appreciation of a game I've been playing for years on and off, and yet there are still many hidden secrets that I wasn't aware of (and certainly would never have unlocked, I just don't have that sort of free time to devote to gaming these days) but just knowing they are in there, and the attention to detail they required to develop is impressive to say the least!
Highly recommended. I can't believe it's taken me this long to pick up one of the Boss Fight books, but I will definitely now be checking out others in the series.
Author 18 books12 followers
I missed the time period when Spelunky was all the craze and even though I never played the game, positive reviews encouraged me to check the book. I'm so glad that I did. I might be a bit biased with my review 'cause I'm working as a game designer and so many parts of the book were like "Yeah, that's it!" moments. It was wonderful to get insight into the creative process behind a special game, pros and cons of many design decisions, reasoning behind the design philosophy which shaped the game and, in general, some life philosophy that shaped the production. Also, I got a feeling that the author is quite down to earth and an intelligent guy so the book tone is like we're having a beer while he shares his thoughts and interesting stories.
So yeah, I'll definitely buy Spelunky after I've read everything about it :D
65 reviews47 followers
A great account of the process of creating one of my favourite games of all time. Yu does a wonderful job of explaining his own creative process and the way he thinks about games, art and the game creation life cycle. There is lots to learn here related to game development(especially of the indie kind), managing projects of the creative variety, shipping games, and an inside look at how the game in question came together over time. The style is conversational and straightforward while delving into a few technical details when required. Overall, it provides a great window into Yu's mind and the reasoning behind several choices that he made. Reading it makes me want to play Spelunky again or go back to making game prototypes.