Rewarding The Players: Valve On Portal 2

[Gamasutra presents here the unabridged version of the Portal 2 interview with Valve project manager Erik Johnson, which originally appeared in the October 2010 issue of Game Developer Magazine.]

Portal was one of those rare game experiences that took audiences by surprise. The simplicity of the interface -- shooting portals onto various surfaces to traverse through levels -- was striking. Layered onto that was the excellent story, mostly driven by the player’s love-hate relationship with GLaDOS, the touchy artificial intelligence that managed the facility in which the game took place.

Portal was a mere three hours in duration, and many felt it was a perfectly defined experience. How does one take that and extrapolate it into a sequel?

Valve absorbed many of the team members for the DigiPen student game Tag: The Power of Paint, using their ideas of painting different effects onto the game world in order to increase scope without over increasing complexity.

But could they really add complexity of design without detracting from the simplicity that made the original game unique? Project manager Erik Johnson tells us it’s all about understanding what will be meaningful to players.

There seems to be a lot of added complexity to the design in general. What was the thinking behind that?

Erik Johnson: There are two parts to that. One is that in the trailer, the one we showed at Gamescom and the one at E3, implies a lot more complexity than exists for a player that plays through the game. We are showing you towards the end of being trained on a particular element.

We thought Portal 1 was the right length for the number of things in the game, the pacing was good. We want to have that same kind of pacing in Portal 2, so the game ends up being a lot longer, but still brings people up on new things at the right speed.

That was the sense that I was getting. It was looking like a longer game in general, because more is happening there. And the personality spheres seem like they have the potential to put more story in there than before. Is that their function?

EJ: Yeah, definitely. Portal 1 was strictly your relationship with GLaDOS. It was just you and GLaDOS. She starts off as just a voice, and is the tormentor of your existence. The personality spheres are definitely this new character in the game -- different than a character in Half-Life 2 that is all about expression, and how they look -- more or less a story-delivery type of character. The reaction people have had to the personality spheres has been a lot stronger than we've expected, so that's good.

I presume that when those personality spheres existed in the final boss battle of Portal, there wasn't an intention of making them part of Portal 2, right?

EJ: No.

One thing Valve doees well is taking elements from previous games and fleshing them out in a sequel or related product. It always feels well-integrated -- how do you go back and retrofit in a way that makes sense in the universe?

EJ: First, the reason why we do it -- especially in Portal 1, there are a bunch of fans of the product already that have very strong opinions about the kind of game it should be. In general, we try to be the servants of their opinion. We try to build the kind of game that they want, and one of the ways to engage with customers is to point out knowledge that they have, like "Hey, we know that you guys played Portal 1," to give them something to hold on to.

And you definitely want to approach all pieces of the game, from story, the way it looks, to how the characters act, in terms of this coherent universe that you can fit things into. A good application of that thinking would make it so that if somebody came up with a given idea, it would be really easy to determine if it would or wouldn't fit. I think Portal has done well in that regard because it is relatively simple in terms of that. And a lot of it is long-term community development, to do those sorts of things.

Portal was a game that many people felt didn't really need a sequel, despite how much fans loved the universe and would appreciate a return. How do you balance that expectation?

EJ: The first thing we did was judge fans by their reaction, and partly because Portal 1 was a much smaller game, they were saying they wanted more -- but what you are saying is really accurate, too.

For many people, it was this perfect experience. It was the game that, far and away, more people finished than any game we've made -- we can see in Steam if the game gets finished, and it was huge in that respect.

We looked back to find the core things players liked about Portal. We felt it was the story and the tone, the type of story it was, and the delivery mechanism of the story. We felt like for a lot of people, their reaction was surprise about the gameplay. Portals are obviously a huge part of the gameplay itself, but the thing they wanted was to be surprised -- like the type of game, what they thought when they played the game.

And music was the third thing. Still Alive is something that people have a really strong connection to. We looked at those three things and said, "Okay, inside of the Portal world, what can we do on those axes to create something that people want.

And with the tagging and liquid stuff, what would you say was the decision behind having that be an environmental effect versus something that you actually shoot out in the original [student game] Tag: The Power of Paint?

EJ: Most of it was just playtesting. We had lots of different approaches on how to change the state of a surface, and this was the one that ended up fitting the best.

Did you actually prototype different kinds of implementations to see if they would work?

EJ: Yeah, the player shooting it -- yeah, lots of different types of surfaces.

To me, it seems that having to shoot anything other than portals would probably add too much complexity.

EJ: There are a lot of advantages of having a game where the gun has the number of states that the portal gun has, especially in terms of players that don't play a huge number of games. It is a great interface with the world that always acts the same way. 

The physics of the original game could sometimes feel complex, and it's sometimes easy to forget which portal is which even though it's so simple. Are you concerned about players keeping it all straight now that the title will be longer and incorporate more elements?

EJ: It's not uncommon for people to use the wrong portal when they are doing it, but take the things that look like tractor beams [in <i>Portal 2</i>]; there's not a huge ramification for the player doing that, because from their vantage point they can generally replace portals. The worst that happens is that they have to re-do it. The portal gun does light up to indicate the last portal you put in the world so you can try to keep track of it, but Portal definitely bends playtesters' brains a little bit.

The trailer I was watching was showing more advanced gameplay, but would it be correct to say there are more timing-while-moving based puzzles? It looks like you have to bounce here, you have to grab this thing while it's in the air and you have to get over there.

EJ: I don't think that would be a true statement actually. It would be a true statement to say those types of demos are interesting to watch to people who have never experienced Portal. It's like the idealized ninja -- we call them "ninja moves" internally.

The Portal experience Portal fans have, where it's surprising in this interesting way -- everyone who liked Portal 1 had that, but it makes for very bad demos at trade shows, since it's kind of slow. It's challenging in the same way, and perhaps even more so than Half-Life 2, where we are talking about the stories, so it's near impossible before releasing the game.

Talking of story, GLaDOS is back, and the comments have been revealed for her this week make her sound like a jealous ex-girlfriend. Is that the intention?

EJ: Yeah. You are the only person she can have interaction with, but the problem is her only way of interacting with anyone is to test them. She can't really kill them, but she can test them. She has no point of being around if you are not around.

It's an interesting dynamic because there's this love-hate relationship going on there. I know the player is just an avatar, really, but what have you discussed internally about what the player feels about GLaDOS?

EJ: Well, there's what the character Chell thinks about GLaDOS, and what fans think about GLaDOS.

I mean the in-game character, yes.

EJ: We haven't really explored a huge amount of what her relationship is. Generally, it's more that the customer would think of how they think. We did a pretty good job of getting customers interested, which was our goal, and GLaDOS is generally not hated in the way bosses are typically hated in video games.

Even bosses that are executed really well, most of the time their goal is to feel like they are a direct antagonist and your goal is just to defeat them. GLaDOS definitely doesn't have that.

Is the aim, if such could be identified, of Portal to escape? Is it the same? Does it matter if it's the same? Having two games with the same end-goal -- I mean, maybe that's not the end-goal, but does that matter?

EJ: Yeah, I think it does matter, but I think the implementation matters a lot more. This is getting tricky to talk about, because it's about story stuff a little bit, but I think if you are telling players that the core of the story is "you are going do again what you did last time," for most people that is pretty unappealing. That's not what is going to happen in the game, but there are definitely some things that are similar to the previous game. In implementation, they end up being fun and different. You're still going to have a testing relationship with GLaDOS.

You mentioned that you tried different kinds of surfaces. Can you talk about any that didn't work and why they didn't? I've always been interested in Valve's playtesting and prototyping process.

EJ: I don't think we are ready to talk yet, since some of them might end up in commentary tracks and the like. Portal's commentary will be, for fans that are interested in things we tried that ended up not working out, should be pretty good stuff.

How do you go about doing a commentary? The game is an interactive experience; in a situation like Portal, it's possible because you have levels, so you can talk about, "Here's what we did in this one, and this is what we were thinking about."

Does it apply beyond games like Portal? How would you do something like that? It's a really neat thing for everybody.

EJ: We usually spend some time really late in the product, as late as we can pull it off, because the later we go, the more interesting things we will have to say. We usually take a day or two, and there's a tool built in the game where anyone on the team can place a node and do a really short description of what they think is interesting.

We have some guidelines as to the types of things that are interesting; one of those is failures, things that we tried that sucked, any kind of non-obvious design thing, like we implemented something, and a different thing is what ended up happening, and iteration of a particular element over time is usually kind of interesting to people, like, "We started here, and we ended up at this completely different thing."

We pepper the game with this huge number of nodes, and usually the writers go through and write a script, so we can record it really quickly. We like to get everybody on the team to talk about something, and we'll go in and record a bunch of nodes, and off we go. It's really been far more successful than we expected. Honestly, we usually assume that most of our stories are pretty boring.

Valve's way of writing seems only possible with an integrated writer on the team. Does writing go through as much revision as gameplay and playtesting?

EJ: It's a hard thing to measure, but I think writing goes through at least as much revision as gameplay. One of the properties of writing is that the constraints around it are far more relaxed than gameplay. For example, you could have this gameplay idea that was really interesting, but it's impossible to make; you could never write code that could execute your idea fast enough, so writing, in some cases, ends up being downstream of some decisions -- it's upstream of some, but it's a lot easier to change.

It's just text, it's very malleable; all it takes is a brain to think about it, it doesn't take 50 people to implement it.

EJ: It gets tricky because you end up having to lock a lot of the writing down; you have to localize it and all that.

How much stuff do you end up having to throw out, in general?

EJ: I'd probably ask [Erik] Wolpaw that. At least some maddening amount, I'd guess. With Portal 2, we've changed the story in pretty significant ways more than once.

You just have to keep it wet; it's way better to make a bunch of bad decisions than to make no decisions, you have to move forward.

[But] It doesn't stop us; we've made plenty of bad decisions.

Yeah, but that's another luxury Valve has: the ability to make bad decisions because of having time and having money by being a company that is mostly beholden to itself.

EJ: Well, and to our customers.

That's very similar in a way, because everyone is beholden to their customers, but at a certain point, everything has to ship, and that certain point is very different for Valve than it is for a third-party developer that may have a publisher breathing down its neck.

EJ: The "making customers as happy as possible" business is a pretty good business. Sometimes it can get a little overcomplicated. When people start having customers other than people who buy their product, like a publisher or someone else, the chance of making bad decisions just goes higher.

When it comes to longevity of gameplay and long-term monetization of customers, how viable are  single-player gaming experiences like this one going to be in the long term?

EJ: I think there is an interesting question in how many projects should be offline products and how long that is going to be viable. Half-Life 1 was a really offline product. I think customers want to find ways to talk about the thing that they are a big fan of with other people, and ideally experience it the same way.

That doesn't mean every game needs to be multiplayer. With single player games that were completely in a box, and there was no way to experience anything else, I think there are things that customers want that those games don't take advantage of.

That could just mean that you want to be able to chat with other people who are playing through the same part of the game as you, or the fans can write commentary nodes in the game and everyone can experience those to take advantage of the fact that there is a huge community of people that want to interact with each other.

I still think the analysis that every product needs to be a competitor in multiplayer, or an MMO, is incorrect; there are a lot of people who want an experience without the stress, so I don't see that changing.

It's interesting to think about  -- numbers suggest that the popularity of guided single-player experiences is dwindling. That may mean that the highest-quality studios will no longer be able to invest in the development of those titles, and thus that type of experience won't improve.

EJ: Part of it is thinking through he reasons for making decisions. You brought up piracy being a reason to not do single player, which I think is a pretty crazy analysis on an issue like that; that's making a decision for your customers about the types of products you are going to build without, by definition, including your customers in that at all.

You're saying that because of these pirates, you get no single player experiences, which makes no sense to me. If there are as much players that want single player experiences, you should go build that. I think there are plenty of people that still want to have single player experiences. Look at Mario; those games do really well.

True, but I feel like those experiences, for adults, are already rare, and will continue to become more rare because it's difficult. Can studios like yours survive without making people essentially pay to level up?

EJ: One thing to think about is, when we are building a game like Half-Life 2 or Portal, monetization is a separate thing that, in the context of the game design, doesn't make a huge amount of sense, really.

We are trying to exploit the psychology of the people that play our games all the time. We are trying to change their emotional state, and trying to predict what their emotional state will be based on what we are doing in the game world.

What's compelling for people, like, "Hey, they're getting a huge reward here, they are going to be happy. They are going to be challenged on the skills that we taught them here and that's going to be rewarding them." There is a non-customer-hostile way to think about what we are doing. There are hostile ways too, though. (laughs)