Technology Trees
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This is part of a series of blog posts on the design process of my web game:

Talking about Ikariam reminded me about technology trees because it has a particularly big and complex one. When I was playing I created a graph showing how to unlock everything so that everyone in my guild could quickly develop as we needed.

In the diagram below, pink rectangles are buildings, green parallelograms are actions, solid blue circles are ships, red hexagons are military units (with their costs), and the empty circles are technology achievements (color indicating which of four tracks). It sounds really complicated and is overwhelming at first look, but it serves as reference for any player with a little experience.

Ikariam Tech Tree (cropped)

It’s worth noting that this is long out-of-date; updates to the game have extensively added, rearranged, and repriced things. I created it with graphviz‘s dot utility. It’s a great tool for easily making the directed graphs that show up over and over in computer science. (And read Anathem, it’s a captivating novel that, yes, prominently features directed acyclic graphs.)

OK, that’s all the “Yay, technology trees are keen!” that I can manage.

The Purpose of Technology Trees

They do have some uses. The first three are heavily intertwined:

First, tech trees linearly organize options over time. If a new player could choose from the start whether they wanted to produce smooth-bore or rifled barrels for their soldiers, they’d have to be a suicidal masochist to choose the former. Usually the later technology uses different, a higher quantity of, or more precious resources (like going from bronze swords to steel swords), but often the improved option is such an large improvement that it’s not a real choice which to use. A tech tree makes it possible to present these things in a linear fashion to players to make the game more rational and learnable.

Tech trees also act as gates on content consumption. Until you’ve reached a particular level of development, you can’t use the warp drive and are confined to exploring your solar system. This makes sure that players don’t skim over expensively hand-scripted characters and hand-designed locations (though most PBBGs procedurally generate content). Gating also ensures that players will have opportunities to recognize all the options presented by content — to continue the example, it’d be easy to overlook your mineral-rich asteroid belt if you could immediately cruise off to the stars, and you might end up hamstrung by lack of iron or the knowledge of where to find it and how to mine it. Gating keeps players from being overwhelmed by options and content until they’ve had some time to read help files and make some new friends they can ask questions of.

The third function of a technology tree is to greatly increase the power scale of players. MMORPGs have infamously large power scales: you go from barely triumphing over garden slugs to slaying gods in a casual manner befitting Richard Dawkins. The game Settlers of Catan has a smaller power scale: you start collecting resources from two towns and could grow to five towns and four cities. Chess has a flat or declining power scale.

The final use I’ve seen is as a sink. High-level players often have more resources than they know what to do with, so they lose the fun of hard choices (like equipment in Tactics Ogre). Technological advancements that provide quantitative improvements (that is, shave some percent off of sailing time as opposed to unlock the ability to build steamboats) act as sinks that excess resources can be poured down. This works especially well when the advancements are expensive, ineffective, and public so that players get bragging rights rather than becoming invincible powerhouses.

Technology Trees Usually Suck

Most persistent browser-based games take those first three purposes and crank the dials all the way up. Players use technology trees to go from pointed sticks to nova bombs, from a small space to the most fertile or productive places possible.

The biggest problem with trees is that they act as ratchets. Once you’ve learned The Pulley you always know it and can’t lose it. That’s fine in a game of bounded duration like Civilization or StarCraft, after an hour or few the game is over your research disappears. You don’t start your second game of Civilization back in the stone age knowing how to produce nuclear weapons. But PBBGs are open-ended, a player has a technology until they quit playing entirely (probably being driven to it by someone farther along).

So players get the height of an even bigger power scale to drop rocks on each other from, and if they don’t have a sink for their extra resources they’ll probably shower them onto a guildmate to ratchet themselves up with.

One StarCraft mechanic often shows up with horrible consequences. In StarCraft, there are a number of enhancements that give special powers to units (such as the ability to burrow into the ground or turn invisible) that mean a defender who hasn’t researched the countermeasure cannot attack those units at all. This works in a 40-minute game where the defender gains access to the countermeasure around the same time the attacker gains the power, but in a PBBG new players may be dropped in next door to someone who has played for months and the countermeasure may be weeks away. Awful!

Designers often don’t recognize how special technology is. A player might gift their resources, raze their buildings, move their cities, fire their workers, discharge their soldiers, quit their guild… but they’ll still have their technology. The advancements available rarely reflect that permanence.

Redesigning Technology

One of the joys of long games like MMORPGs and PBBGs is that they give players the opportunity to eventually try everything the game has to offer. Well, unless the player has to make an irreversible decision like character class, then they create alternate characters or logins and decry the grind back up through the tree.

Looking at StarCraft again, I’ve combined two mechanics to design an improved technology mechanic for my game. First, limit permanent technological advancements to the expensive but low-productivity sinks mentioned above. In StarCraft you produce advancements by constructing certain buildings or spending resources at them, like a Spire to be able to build flying units. If you lose the building, you lose the advancement and can’t build more flyers. The other mechanic is “supply points”, a cap on the number of units you can control at once. Certain buildings and units raise the point cap, and most units count for 1-2 points toward the cap. It’s not a resource you can bank, spend, or trade, it’s solely a limit to the number of units you can recruit. It prevents armies from growing too quickly in the beginning of the game and growing too large in the end of the game.

Combining these two ideas, players could build research buildings to unlock different abilities and advancements. They can’t unlock everything because the cap on research buildings is lower than the number of abilities. Abilities stop being an oddity and are better integrated into the rest of the game mechanics — do you spend your money setting up a gasoline engine plant or buy more horses? Players choose where to specialize based on their opportunities and personalities and can raze and rebuild buildings to change their selection.

This is the eighth and final of a six post series on game design, weighing in at a surprising 6,200 words (I didn’t originally plan on these two tangents, but let’s all toast Douglas Adams while I’m about it). I’ve noticed I’ve picked up some new readers, so let me again let me say I really appreciate feedback. I’m going to return to my regular babbling about whatever shiny thing captures my attention — which is to reiterate that you should feel free to comment, email, or IM because that’s where I tend to pick up topics from.

The Farming Genre
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This is part of a series of blog posts on the design process of my web game:

I mentioned I have a rant about how I think of most browser-based games as belonging to genre called “farming games”. The defining characteristic is that they are about farming other players or being farmed until you quit in disgust.

You build a city or an empire and you usually can do exactly two things with other players: trade resources or fight. To fight you build some military units and point them to sack some other player. A few hours later, if they overcome the defenses, they cart back some loot for you. The game’s leaderboard ranks by how many resources you’ve gathered (or some derivative like number of upgrades purchased), so the more loot you haul in the better.

When you’re collecting resources and upgrading your cities there’s a positive feedback loop at work: you can build a bigger sawmill, hire more children to mine, reach a faster warp factor on your starships, all so you can bring in more resources. Games often address this by making upgrade costs grow multiplicatively or exponentially while the returns increase linearly, but usually the rate of return grows faster than the rate costs increase. If that last sentence made your eyes glaze over, think of compound interest: the more you have, the faster you earn more. The rich get richer.

So every additional resource helps, especially early on. Players have a strong incentive to attack each other for a bit of loot. Well, not each other — you might lose the resources you invested in your army. Players have a strong incentive to farm the weakest available players, which is roughly synonymous with the newest players.

Farming is the act of treating another player as a resource farm. By sending wave after wave, the attacker guarantees the defender won’t have the resources to build defenses and, if they try, will only be able to finish a small percentage that will be snuffed out before it grows to effectiveness. The defender will never get out from under an attacker’s thumb, they’re reduced to passively generating extra resources the attacker uses to grow even faster. The word farm is not hyperbole.

Players grow in power over time, there’s little skill involved. Players have to schedule their upgrades well (eg. make sure to harvest crops before building a refinery that would employ new workers who would otherwise starve), but the dominant factor is exponential growth over time (applying this situation to capitalist economies is left as an exercise for the reader and college freshmen who have just read Marx for the first time). The best players to attack are new players, they can’t and often don’t know how to defend themselves. If you want a picture of the future, imagine a boot stamping on a newbie face — forever.

If you think I’m belaboring a really obvious point, congratulations, you understand game design better than the creators of farming games.

Some designers realize that it’s a problem and have worked to mitigate it. New players receive automatic protection for their first week of play and can’t be the target of any attacks. This just pushes it back, of course, making the most fallow farms players who are seven days and one minute old (and this is usually when the first attack arrives). Some games restrict players from attacking anyone more than a few rankings above or below them, but that just means players shift to farm whichever player is at the very bottom of their allowed range.

Another approach is to give players a hideout, a storage space for resources that can’t be looted in an attack. It’s hard to thrive, though, when you have to spend all of your resources upgrading a hideout to store enough resources to buy the next enlargement for the hideout… and repeat until you can afford to invest in upgrades that allow you to collect resources faster or build an army. (And if attacking players can raze your buildings instead of only military units as is typical, the situation is even more bleak.)

I’ve seen one game that allows you to hire the Imperial Army to come protect you. For 20% off the top of your resource income they’ll send a detachment of soldiers that can fend off the typical army of any player younger than a month or so. For 40%, you regain your newbie protection and can’t be targeted at all. I’ve seen a few games that will cut out the middleman and and build a mechanic to allow you to directly pay the protection money to your farmer in return for this arrangement being prominently visible to other players, the presumption being that others attackers will stay away rather than risk picking a fight with someone their own size.

But these percentages bring up that feedback loop again. If you’re getting farmed or paying protection, you’ve lowered your rate of growth. Your attacker’s stays at 100% or is inflated by the resources they’ve farmed (directly so in the protection racket). The newbie will never be able to challenge established attackers, and players who don’t farm will fall behind and become farms themselves.

Players can band together into guilds for mutual defense, but this only serves to shift the problem from individual players to guilds while making life worse for lone players. All of the above still applies.

I’m going to skip recounting the less-popular and equally ineffective counters and ask: What’s a newbie to do? Quit, obviously.

I can only wish I had metrics for these games (they’re not generally run with the care and attention that lends itself to gathering data for analysis), but the dropout rate is huge. I’d guess most farming games lose at least the bottom 80% of players every month.

The players who grit their teeth and hang in there or have the luck of a little quiet to set up their own farms are typically amoral teenage boys. They’re not good customers and they don’t form a healthy community. The prospect of living in a lawless world populated by violent psychopaths with gutter mouths isn’t generally appealing, further thinning the ranks of newbies.

I didn’t expect to rant at such length, but this is why I didn’t start building a game of my own ten years ago. I couldn’t see how to fix this problem without giving up on persistence altogether. Playing WeeWar was an inspiration because I realized that browser games don’t have to be slaves to persistence to be fun and I read David Sirlin’s insightful blog posts and book on multiplayer game design that I’ll cover in depth in the last post on game influences.

Game Influences (2/6): WeeWar
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This is part two in a series on games that influenced my design for a web game.

WeeWar is a turn-based strategy game for 2-6 players. Starting a game is as simple as choosing a map and recruiting opponents. Each base you control earns you money to spend producing units. You advance across the map and win by smashing enemy units and wresting control of all the bases.

The core of combat is fairly rock-paper-scissors: infantry beats tanks, tanks beat vehicles, vehicles beat infantry. You manage your flow of units to the front to bring the right weapons to bear without ceding ground (and, hopefully, fighting on favorable terrain). Artillery units can decimate opposing units but are weak and must keep their distance. Air and sea units add further complexity.

WeeWar battle

WeeWar’s mechanism for taking turns is very nicely done. You and your opponents don’t have to be online at the same time for the length of a full game because you get 24 hours to take each turn. If both you and your opponent are online at the same time and taking turns promptly you can play most maps in under a half-hour. But anytime that your turn comes up you have a full day to make your move, so it can play like correspondence Chess where you and your opponent alternate moves once a day. You could play several games at once and only play when you have fifteen minutes free to take your turns.

WeeWar is like a perfect translation from board game to the web (though it appears to be based on the Game Boy game Advance Wars). The interface is crisp and responsive, it’s easy to arrange games and chat with your opponents. The web browser just falls away and only the game matters, a sign that knows how to use its medium to its fullest. The genre couldn’t be more different from web games like Ikariam.

Instead of building up a long-lasting empire or RPG character, you’re in standalone games that each last a few days, nothing carries between battles. It’s a bit of a downside, too: there are no persistent relationships you can form with other players besides adding them to a friends list to see when they’re online. When you finish a game, there’s no mechanism at work to draw you back to the site to play again.

WeeWar (besides being fun to play) inspired me to break from the mold. I hadn’t considered the medium and genre separately, so my designs were all very derivative and uninteresting. I decided to try to find a balance between the long continuity of Ikariam and the short sessions of WeeWar because each is a different kind of fun and a incentive to play.

Next, I’ll talk about a role-playing game called Tactics Ogre.

Game Influence (1/6): Ikariam
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This is part of a series of blog posts on the design process of my web game:

Ikariam city view

Ikariam is a persistent browser-based game. In a game world shared with thousands of other players, you found and improve cities that grow over weeks and months. Nearly everything takes time to happen: you start construction of a building and it may finish in 40 minutes, you recruit 20 swordsmen and they arrive at five-minute intervals, or you make a trade with another player and the resources arrive in a few hours (depending on how far away that player is). It’s a very slow-paced game, you can enjoyably and play fairly competitively with a few minutes in the morning and evening.

I’ve played a few dozen games in this medium and genre (more on that distinction in a minute), and Ikariam is the best of them. It’s beautifully polished for new players: sharp, consistent graphics, an instructive tutorial in early play to get you started, clear help files, and overall high production values.

It’s also very smart about multiplayer. While building your cities is fun, the multiplayer interaction is the strength of these games. You compete for resources, offer trades, make friends, forge alliances, and fight battles. These things could all happen in a single-player game, but interacting with real people is what enlivens these games. You can see that power in the success of World of Warcraft and Facebook.

Different views of Ikariam

Actions cost resources, and there are five in Ikariam: wood (most common resource, for buildings and units), marble (for advanced buildings), wine (for population growth), crystal (for research in the technology tree), and sulfur (for military units). Ikariam has some clever design elements to induce player interactions. It starts with islands that group up to 16 cities.

Each island produces wood in a sawmill and any city can donate towards upgrading it. It doesn’t matter who donates, every upgrade means every city can produce more wood. This uses the free rider problem as a game mechanic: there’s a natural tension between wanting your neighbors to pay and not wanting to aggravate them by under-contributing.

In addition to wood, each island produces one of the four other goods. Because your city needs all four to thrive, you’ll have to barter, trade, beg, extort, or raid them from other players. Eventually you can found cities on other islands and transfer your own resources around, but that’s not always adequate to meet the demands of your growth.

They’re simple mechanics that are powerful in practice. They give players natural excuses to start talking to each other, form opinions of each other, helping or hurting each other. In short: to play.

Most of these games get this wrong, players are self-sufficient or can only interact in destructive competition (eg. military attack). I’ve said “these games” a few times, let me define that a little better. The medium is a persistent browser-based game: the defining attributes are online browser play, hundreds to millions of players, and long-term play. The genre is… well, it doesn’t really have a name. It’s about building an empire, probably crushing other players, moving around resources and military units. I personally call them farming games, but that’s the subject of a later rant.

I think part of the appeal of these games is that people don’t tend to have a lot of productive, creative hobbies anymore. It’s unusual to build a ship in a bottle, knit a sweater, or refinish a table. Building a city, an alliance, an empire, is sort of a virtual exercise of this same muscle. I really enjoy these games and have been half-planning to write one for years.

But as I look at how the genre is has been mapped out I see a narrow playerbase and shallow gameplay. I started seriously thinking about building a game when I realized that I can have the medium I really like without the genre that I am increasingly disenchanted with. My next post about game influences is about WeeWar, a game that does just that.


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