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Diablo 3's Ability System

Diablo 3's ability system is a major step forward from Diablo 2's. Blizzard has embraced the idea of letting players fully explore any build they want at any time, and also solved the problem of experts "needing" to switch builds every encounter.

David Sirlin, Blogger

May 7, 2012

13 Min Read

Diablo 3Diablo 3 comes out next week. I'm giving it the coveted award for "Biggest Comeback In System Design." Diablo 2's ability system was so bad that it's almost unbelievable, while the way Diablo 3 handles ability customization is one of the very best systems I've seen.

Diablo 2

Diablo 2 had talent trees where you spend points to unlock new abilities, very similar to how talent trees work in World of Warcraft. Also, you could allocate stat points into various different stats however you wanted as you leveled up. At first glance, these seem like ok things, but let's look at just how deeply problematic they really are.

Don't Use Points!

First, the best way to play Diablo 2 is have this big red "+" button on your screen almost the entire time, the one that says you have extra points to spend. The reason that will be on you screen for weeks is that you'd be a sucker to actually spend the points as you get them. You counter-intuitively (and unfunly) should stock up on those and spend them much later on. So the simple and fun thing to do (spend points as you get them) is just a trap for noobs.

Next, the whole system of allocating points in the first place didn't really customize anything. It was just a giant test of if you did your web research enough to know the only reasonable way to spend those stat points. You don't have to take my word for it either, let's see what Jay Wilson has to say. He was an avid Diablo 2 player, and the Game Director of Diablo 3 for the last 5 or 6 years.

Here's a written transcript of the relevant part, in case you don't want to watch the vid:

"You usually take as much strength as you need to get the armor that you're targeting, and that's usually around 120 or 220, depending on what type of armor. You take 75 dexterity because that's the amount you generally  need for good block percentages. You take NO energy at all unless…there's like one type of build you can make on a sorceress that uses energy shield. And then you put everything else in vitality. That's a shitty customization system. That's just not a good system." --Jay Wilson, Diablo 3 Game Director on Diablo 2

Talent Trees

Next, there's the talent trees. There's two problems here, one medium sized and the other is one of the most mind-blowing fumbles in design out there. First the medium problem: it's pretty hard to make talent trees that give any real choice. They sure seem to allow choice, and in theory they really could, it's just very hard to balance it all so that there's a lot of good builds. Blizzard learned this in World of Warcraft, and I think we can see a clear progression in their thinking here. The first thought was that talent trees are great (and I was on board with this). Then there were too many talents that were "required" because they were so damn good, you couldn't pass them up. Stuff like +5% damage, you just have to take that compared to various utility skills. Blizzard reworked all the talents (well several times, but I mean one time specifically) to get rid of all those "required" talents. If something was just +damage, they mostly got rid of it as a talent. If a talent was an ability that was *necessary* for a class, they just gave you that ability outside the talent trees. So now what was left allowed for more flexibility in your choices.

I was on board with that, but it kind of didn't work that well in practice. Blizzard then gave it yet another try, trying to open up the reasonable choices even more. The next step in their progression in WoW talents was to get rid of the trees entirely, for the Pandaria expansion. In the new system, you will pick one of three possible talent powers every 15 levels. (Here's the Warlock one, for example.) Diablo 3 takes an even further step in this progression, but let's come back to that. There's one more thing about Diablo 2.

Start The Entire Game Over To Change Even One Damn Talent Point WTF

In Diablo 2, you can't respec your talents. Just think about that for a minute. If you spend a talent point wrong once, you have start over your entire character. What? Yes, really. If you want to try out a new ability and see what it even does...you have to start over your entire character. This is completely ludicrious. The best way to play the game is actually to download a hack that lets you set ability points to whatever you want instantly, just so you can see which build you might want to play, then go back to the real game. I've seen many players defend the lack of respec as "replayability" but that's not what replayability actually means. That's just an enormous time sink for no real reason and it severely damages the play experience. (Note that 9 years after Diablo 2's release, there was a respec thing you can do, if you jump through some hoops. Too little, too late.)

Years ago I saw several official Blizzard posts that defended a similar idea in World of Warcraft. Their claim was that the intentional difficulty (and originally, the complete inability) to respec talents was to create more diversity, and to make choices matter. This is really wrong-headed and actually the opposite of true. If you have a balanced system, you would not have any need to prevent everyone from switching their specs around. You're basically saying that you're happy that a lot of people are locked into bad specs they aren't happy with, because that means there are more different specs out there being played. What a terrible thing to inflict on your players. Again, you'll have varied specs out there if you actually have several viable ones and small or zero switching costs. Imagine if we made a fighting game and "balanced it" by saying you are stuck with whichever character you first pick! The big variety of characters played shows how great our balancing is right? (No.)

The no-respec mindset is actually counter-productive to the goal, too. When switching costs are really high (like creating your entire character over from scratch...) then no one really wants to experiment. It's too risky to do so, and it's better to go look up the cookie cutter build and go with that. So you get less variety, not more. The variety you do get is often from players who you pissed off by punishing them for mistakes or for exploring the system.

The good news is that Blizzard's thoughts on this have clearly changed over the years. WoW respecs got more permissive over time, and the next step in that progression is Diablo 3.

Diablo 3

Allocating stat points as you level up: gone. Great, this was busywork that contributed basically nothing, so the subtractive design makes the game more elegant overall.

Talent trees: gone. You have exactly 6 slots for abilities, and you can put whatever you want in those slots. There are approximately 24 abilities per class, so your build involves making meaningful choices about what to keep and what to leave out.

Runes: interesting new feature. I read that this system took far longer to design than any other system in Diablo 3, and I totally believe it. When I first saw the interface in the recent open beta test, I couldn't believe what I saw. I was so blown away, that I had to go read about it before clicking on anything because it appeared too good to be true. I think this actually happens a lot in design, where when you finally create / see / experience the "right answer," it seems so obvious, like it couldn't have been any other way, but it might have taken years for the designers to figure out that answer. Elegance is hard.

Here's how runes work. A rune is a modifier to an ability. Every ability (each of your class's 24 abilities) has 5 runes associated with it. And I don't mean the same 5 choices, these are custom for every single ability. You can only have rune selected for any given ability. So that means you have to choose if you want your Magic Missile to have 1) increased damage, 2) split into three shots instead of just one, 3) pierce through enemies and keep going, 4) generate mana ("arcane power"), or 5) track the nearest enemy and do slightly more damage. Here are the abilities for the Wizard, along with all their possible runes.

So the combination of possible builds here is ridiculously large, given that you fill each of 6 slots with one of 24 abilities AND for each of those 6 abilities you chose, you also choose one of 5 runes. Oh and you also choose any 3 out of 15 possible passive abilities for you class, so even more combinations.

Infinite Instant Free Respecs

Now here's the part that was too good to be true to me. You don't spend points on these runes. You don't muck around with them in your inventory. You don't commit to them and have to pay some annoying respec fee or something. At *any time* you bring up the ability menu, set which abilities you want, and for each one click on the rune you want. It's all in a nice menu with no hassles. Again: any time. With no cost. As much as you want. The only drawback is a three second cooldown so you don't do this in the middle of a fight. Wow!

As you level up, you automatically gain new abilities and runes. Gaining them requires no action on your part. And at any time, you can switch amongst any abilities and runes you have so far, eventually all of them. You can fully explore the system all you want. You can see what every ability does. You can try out any combination of abilities. The freedom is amazing and it shows newfound confidence from Blizzard. There is no need to slow the progress of people figuring out good builds: Blizzard is telling us that exploring builds basically *is* the game, so go for it.

Elective Mode

I do have one minor complaint here. Internally, Blizzard said they divided the abilities into different categories that helped them think about what's what, then they realized that players should be able to see these categories too. So they exposed them, and tied them to the 6 different slots you have. I think this worked really, really well. It makes the whole system easy to understand, elegant, and imposes an interesting restriction: that you can only have one ability from category one, one from category two, and so on. It would be absurd to think you don't have enough choices, because you actually have over 29 BILLION possible builds per class with that system.

But really, I think Blizzard had already done a lot of development that assumed you could choose multiple abilities from a category if you wanted. They were maybe already too far down that road. So while their new system is easy to understand, elegant, and has an interesting limitation, you can turn on "elective mode" in the menus to get a less elegant UI that lets you put any ability in any slot. And of course you have to because it's strictly better for you to remove that limitation. So yeah, too bad they couldn't have made the simpler concept with better UI and the category limitation work. But whatever, it's fine.

Nephalem Valor

There is one more surprisingly great thing about the Diablo 3 ability system. That you can respec at any moment as much as you want does create one problem. If you are super hardcore, you will have a different spec for like every encounter in the game once you have memorized it all and are farming for items. That means the best way to play is tedious once you reach that level of mastery. It would really suck to "fix" that by limiting the respec in any way though. Normal humans want to explore the system freely and I'm so blown away by this infinite, instant, free respec thing that we should NOT ruin that to address this hardcore problem.

Of the top of my head I thought, "Hmm, maybe have a separate mode where respecing sucks or something, let hardcore people play that." But Blizzard's answer is much better. The Nephalem Valor system kicks in at the max level (60). So before that, meaning your first run through the game, you really can respec all you want for free with no drawback at all. Go for it! Once you reach 60, you can get a buff called Nephalem Valor that can stack a few times, maybe up to 5. Each buff increases your gold find / magic find stats. Also, if you kill a boss with that buff on, the boss will drop extra loot. You get the buff by killing rare or champion monsters.

The genius part is actually how you lose the buff though. I think it lasts about 15 minutes, so you have to keep progressing to stay buffed. But you also lose it if you *leave the game* or if you *change your abilities or runes at all*. Ok think about that. If you plan to farm the same 3 minute segment of the game over and over and over, you can do that. But you'll be doing it without the buff so it won't be optimal to get rare items that way. Also, if you want to respec before every single encounter, you can. It's just that you won't have the buff so it won't be the optimal way to get items either. The optimal way to get items happens to line up with the fun way to play: to go an entire big run where you stick to one spec. This is a very clever way to solve the problem for the new player and the expert without really sacrificing anything. 


Thanks to Jay Wilson and the rest of Blizzard. I think this ability system with 6 slots, the lack of tech trees, the 5 runes per ability, the infinite instant free respecs, and the valor buff system overall is a very solid design. I'd go so far to say that it advances the craft of game design, even. Blizzard has come a long way in designing these kind of systems, and I think they've finally nailed it.

--David Sirlin
reprinted from www.sirlin.net
My kickstarter for the Puzzle Strike deckbuilding game 

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David Sirlin


David Sirlin (www.sirlin.net) is currently a Producer / Game Designer at Backbone Entertainment. He's a multiple-time national Street Fighter tournament champion, author of the book Playing to Win, co-organizer of the Evolution Fighting Game Championships national tournament series, past member of Street Fighter Team USA (representing America at an annual international tournament held in Japan), and one of the main subjects of Bang the Machine (a documentary film about the competitive Street Fighter scene). He also did a two-year stint in the World of Warcraft.

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