Interview: Valve on their insane Portal 2 ideas

Tom Francis



I was at Valve last month to interview pretty much everyone I could find, and play one of the most exciting PC games on the horizon: Portal 2. The preview I wrote, and the profile on Valve themselves, is in the new issue of PC Gamer in the UK . But we're also putting up the interviews here on the site, one a day for a week.

Yesterday Gabe and co told us about Valve's failures , and Wednesday's interview was about Valve's big surprises . For today's, I had the brain taxing pleasure of playing Portal 2 in co-op with its project lead Josh Weier, while interviewing both him and writer Erik Wolpaw. I'll explain what's going on in the game any time it's relevant to what they tell me, and I have of course cut out a lot of, "Put one there. No there. No, don't jump in the slime. WHAT'S WRONG WITH YOU?"

Josh (left) is a software engineer, and Erik (right) wrote Portal.

PC Gamer: It must be interesting going from a programmer to a project lead, to have an instinctive sense of what's possible and what isn't, whereas if you're just from a design background I guess you have to learn that stuff as you go.

Josh Weier: I think for better or worse I have an engineer's mindset going about things, where I'm breaking down things in the process, and that's actually a really Valve thing to do, anyway. Even our lead designers and artists think that way, it's really a culture thing, which is cool.

As you can see, both you and I are robots. We made that choice because when we started to think about Portal 2 co-op, one of the things that became obvious is that players just want to have fun. There are a lot of ways to drop your buddy in the slime, and do things that would accidentally kill your friend and it was really funny and everybody really enjoyed it. We wanted to play that up, but we didn't want to make that grotesque, because if it were Chell it would be gory, and not that funny.

And there's another aspect to that that we really wanted to hit on that we'll show you in a different map, which was making those deaths more comedic. But also when a player dies, we simply respawn them and the map continues, we didn't want to put in a big penalty for death. We wanted people to be able to make mistakes and have that be a funny thing that you both talk about. Not something where you're like, “Argh, I hate my buddy!” and then punch him. So that was a driving goal for us. I don't have a great way to show you this but-

PC Gamer: What do I look like?

Josh Weier: Ah yes, let's show you that. You can see you look more like a turret, and I look more like one of the little personality spheres. Do you want to talk, Erik, and I can drive?

Erik Wolpaw: Yeah. So, it's Portal, but each of you has a portal gun so each of you can fire a pair of portals. Your two portals are always linked to each other, and your partner's two portals are always linked to each other, but either one of you can go through either of your portals. The portals never get interlinked, so one of my portals will never get linked to one of your portals or vice versa.

(I wave stiffly)

I think you just hit a gesture. There's a whole bunch of context sensitive gestures as well, there'll be more as well go towards shipping. There's some laughing, there's probably some dancing in there.

PC Gamer: I'm so, like, awkward.

Erik Wolpaw: Yeah, one of the things the animators are going for with the gestures is that they're robots trying to imitate human motions. Some of these aren't finished, but the gestures play into the co-op story. The co-op is a completely different track from the single player. It fits into the single player fiction but it's its own little side story.

It's about length. The single player's about six hours, and the co-op is about six hours currently, give or take a little by the time we ship. But these characters appear in the single player game. Once you play the single player game it becomes obvious where this sort of happens, in terms of the single player fiction.

(At the end of the puzzle, Josh and I are ripped apart and sucked into tubes.)

Erik Wolpaw: Oh yeah, that's the... basically at the end of the levels, instead of riding elevators you get disassembled and reassembled. It was one of the reasons we made them robots. In single player death has some consequence. In fiction you die and that's the end of the game. Here, because you have a partner, we need you to be able to come back over and over again, so the robots can be built.

This is an example of a slightly more complicated puzzle here.

(We're in a large room full of slime, lasers and spiky crusher machines.)

Now what Josh is going to do is de-power the crusher, which will bring it down. The lift is going to go down and the one that's over here is going to come up. So what you'll need to do is-

PC Gamer: Jump to the lift without crossing through the beam?

Erik Wolpaw: Ah! But, you can't actually jump that far so you're going to have to think about-

PC Gamer: Portal to the lift!

Erik Wolpaw: Yes, portal it.

Josh Weier: Okay, tell me when you're ready.

PC Gamer: Apparently I'm ready!

Josh Weier: Okay.

PC Gamer: Wait. I'm facing the wrong way.

Erik Wolpaw: Woah. Oh god! No! Wait, no you're okay, just jump, jump, jump!

(I make it, and Josh manipulates the level for me to get to the exit. Once there, I have to manipulate it in turn to clear the way for him to join me.)

GLaDOS: As an impartial facilitator, it would be unfair of me to name my favourite member of your team. However it's perfectly fair to mention it in a way that my least favourite member probably isn't smart enough to understand. Participant Orange, you are doing veeery well.

Erik Wolpaw: She's trying to break you two apart. We have a whole series of puzzles that are asymmetric in that way, where one person has a specific job to do and helps guide the other person through the puzzle, and the other person has more of an execution role. This is another new element. These are laser bridges. What happens is, if you put a portal at one end of the laser bridge, and put another somewhere else, the bridge will extend.

PC Gamer: Oh nice.

Erik Wolpaw: Yeah, so you can navigate through there. We're kind of cherry picking levels in this demo from all over the place. There's no real progression in terms of what you might have been trained on.

One of the things is, in the single player campaign and in Portal 1, there's buttons, and boxes you place on the buttons. In the multiplayer game there's also these balls that go on a different type of button. The big thing about these balls is that they bounce, so it means that you need to get under it or else it's going to bounce off of this thing.

(In the ensuing puzzle, I have to use my portals to extend a light bridge over Josh's head in mid-air, so that a jump pad doesn't knock him into a vapourisation field. After he hits his head on my bridge, I have to quickly move it beneath him so that he also lands on it. In return, he extends the bridge to me with his own portals, I walk over and he passes me the ball he's carrying.)

GLaDOS: The two of you have forged an excellent partnership, with one of you handling the cerebral challenges, and the other ready to ponderously wander into action.

Josh Weier: One of the fun things about co-op is sometimes making mistakes is more fun than getting it right straight away, because you're trying to figure out how to come back.

Erik Wolpaw: Yeah the animators are going crazy with death animations to try and, you know, all the different situations you can die, the goal is for them all to be entertaining.

Right, so this puzzle. In single player, in Portal 1, and in Portal 2 as well, we try not to do a lot of timed puzzles, where there was time pressure. But in the co-op we actually found that it was a lot more fun to do the time stuff with a partner, where you kind of come up with a plan and then execute it, and this is an example of one of those.

Josh Weier: It's funny with co-op, because one thing we discovered really early on is that we could throw really hard problems at players in single player that stump them, and they'd get tired and they'd go off and look online for a solution.

In co-op, there's this really interesting thing where because you're talking to someone, you're talking about your process:

“How do we get to the button?”

“Oh, I don't know. What if we did this and this?”

And just like in real life, communicating that way, you suddenly go, “Oh, it's this!”

So there's a lot of cool moments in co-op where your buddy goes, “Oh I know how to do it, I know how to do it!” And then he gets it wrong. And you're like “Oh I know how to do it I'm gonna do it!”

And so there's this really neat back and forth that occurs with doing that. It gives you those “Aha!” moments in Portal, but it's all the more cool because you've got your buddy there doing it too, and that's really neat.

PC Gamer: There aren't really that many co-op puzzle games, are there?

Josh Weier: Not a bunch.

PC Gamer: It's funny because if I'm in the office and I'm playing a shooter, if someone's looking over my shoulder, they're not saying “hey, throw a grenade there” or “try shooting that”. But whenever there's a puzzle game there'll be a crowd that gathers, and everyone's suggesting stuff.

Erik Wolpaw: That was the thing. Anecdotally, as soon as we shipped Portal, just from people who work here, we kept hearing the same story over and over again, which was “I played it with my son, or my daughter, I played it with my wife or girlfriend and we played it co-operatively.” I mean, right from before any other decision was made about the sequel we knew that was something we wanted to put in, to formalise the co-operative nature of it. Having said that once you bite it off there's all sort of unforseen things like some easy to solve, like, put a portal here, we quickly realised you needed another way to do that. But just other things, wrapping your head around what the puzzle design for four portals is. One of the things is that each puzzle must require four portals to solve. So in other words, if one person can figure out how to solve it with just one set of portals then it's back to the drawing board, so it's a whole different set of design problems with the co-op stuff, which also meant that, whether we wanted to make it a separate track or not, it had to be a separate track because it doesn't work in a single player track, the puzzles are just different.

Josh Weier: I think one of the things that was interesting about that, too, is the fact that if you remember in the original Portal, like, just learning what portals were was really exciting, and suddenly adding four portals to the mix gave us all these things where that was happening again, so it kind of took you back to that place of like “yeah I know how portals work” and then you add another pair and it's like, oh man there's all these things that suddenly come up, and that was really fun to explore again.

Erik Wolpaw: It was interesting for the team, because it reinvigorated the portal concept, you know, after a few years of thinking about them and all of a sudden they seem fresh again. Having said that all the new puzzle elements, single player and multiplayer share. Everything that's new in the single player also appears in the co-op, and vice versa. I don't know if the balls appear as a puzzle element in the single player, but that's about it.

Actually the other thing that seemed obvious at first was “Oh, we've got to do portals in some way that's competitive.” And, I don't know, we did four or five iterations of that. In theory it all sounds kind of fun but it quickly devolves into just, a not particularly fun chaos, because they're not really puzzle oriented.

One of the things we did was a football thing where you had to grab a ball and you had to put it somewhere, and you could drop people into portals and you could use portals to get further down the field with it. It was kind of okay, but it wasn't especially fun.

Josh Weier: Yeah I feel like the co-operative puzzle solving is somewhere where the game really shone and, like you said, there's so many competitive co-ops that it's kind of a weird place to put it.

Erik Wolpaw: All of a sudden you're competing with both sports games and shooting games when in fact it's not like the co-op puzzle space is so oversaturated with titles that it just felt like a way better avenue to pursue.

PC Gamer: Was it just frustrating to be shoved through someone else's portal by them firing it at your feet?

Erik Wolpaw: Yeah it's not as satisfying for either party as you thought it would be in your head when you imagined it because all of a sudden you're just falling. It can be disorienting going through the portals when you've placed them yourself and when you didn't it's just really disorienting.

Josh Weier: It ended up devolving down into, I think at one point, we had eight people in a room all trying to do that and everybody bunny hopping to try to keep away from it. It was interesting internally but I don't think it's the kind of thing that people are going to have a lot of fun with. And we had a laser in there, and people were zapping each other. That was exciting.

Erik Wolpaw: Yeah, that was alright. Anyway, it took a while to hook that up, and then about five minutes to realise that we made a terrible, terrible mistake.

PC Gamer: Do you have any bits in the co-op campaign where you have to split up and you have to solve puzzles using two portals?

Erik Wolpaw: There are some parts where you do separate briefly, there aren't a lot of puzzles that require you to be completely out of each other's sight too much. I can't remember what the thinking was, part of it was, we wanted to keep you together as much as possible. The thing that is more along those lines are the asymmetric puzzles where one guy is hanging back, kind of controlling. There's one, I think it's in the teaser we're doing, which is like, it looks like a big ant farm where there's things moving around and there's one guy controlling that while the other guy's trying to navigate through it. Basically, the asymmetrical puzzles kind of fulfil that role where you're separate. There are a few places where you're separate. The one thing that we discovered is that because you may be sitting front of a TV, hopefully a lot of people will play it split screen on Xbox, having GLaDOS talk to you asynchronously is difficult, because if you're sitting right next to each other then it quickly just becomes noise.

Next page: the Portal 2 that didn't have portals in it .

PC Gamer: So does GLaDOS say the same things to both of you?

Erik Wolpaw: Yeah. We actually toyed, at one point, with having GLaDOS saying one thing to one player but she's whispering another thing to the other player. But that wasn't working for various reasons, plus it would have required twice as much content - because we also needed a complete story that didn't have that, for when you were playing split screen. It was kind of fun for a little bit but for the effort it would take to replicate a completely different story without that... the joke wasn't so good that it was worth doing that.

The other idea was supposed to be, in this one section, that GLaDOS is trying to drive a wedge between you. And because she's GLaDOS, we figured people would be on board with that, clearly knowing that you were actually supposed to bind together. But people didn't actually really like being– anything that smacked of competition, we got negative feedback about.

She was doing this thing where she would start randomly assigning points for doing nothing, basically. But people would try to figure that out and they would be like “I want these points!” And they were meaningless. She was just arbitrarily assigning points. Sometimes they weren't even points, she'd give you, like, four pineapples or something. It didn't make any difference they were just some code of her own.

For most people it just wasn't working. It sounded great in theory, it's still a good joke when you say it, but in the actual playing of it it was falling a little bit flat. It was a) confusing people, and then b) making them angry.

Josh Weier: And there was this weird social thing that people would do that was kind of cool, where one person would go through the door and get some points, and the next time around, before they went through the door they'd say “No no, you go first”. So they were actually trying to game that and help each other out. So that was kinda cool, but, yeah, drove people the wrong way.

PC Gamer: Yeah, points are never meaningless.

Erik Wolpaw: Yeah, that's what we found out! Points are never meaningless.

Josh Weier: We did some mean things, too, where you would do the same things and she would award one player more points than the other, and that drove people nuts.

Erik Wolpaw: Yeah, exactly the same action would result in differing amounts of points.

PC Gamer: But you've still got some references to that in there, right? I mean we heard it.

Erik Wolpaw: Yeah, and we may actually end up shipping with a little taste of that. I was like, “I'm going to extend this [joke] out for six hours, and it's going to kill for six straight hours!” and it didn't. But maybe for six minutes it'll kill. For one chamber, we'll probably get the gist of that out there.

Josh Weier: The great thing is that we always go through tons of play testing so we tweak it, so we put it in there and see if it works. If it doesn't fly we don't need to do it.

PC Gamer: I've heard something to the effect that Portal pretty much done a year before shipping, and that year was spent play testing. Are you going to be able to give it that much testing this time round?

Josh Weier: Yeah, I think kind of from the core of it we've started with that approach. We would work on the tractor beam or whatever it was, the excursion funnels as we call them online, and it was just a matter of sitting down, seeing how people played it, making puzzles, figuring out the next puzzle. And they just go through, I mean, it must be hundreds of tests by the time they're done with it.

So clearly, we need to definitely put that same love through all of it. Weekly we'll run it through and have the whole game played by people, we'll bring in total Portal newbies, we'll bring in Portal pros and we'll bring in everyone in between, just trying to make sure that everybody can have fun and get through.

Erik Wolpaw: We had one our accountants or somebody on Friday who'd never played Portal and who doesn't really play games, and she floundered a little bit. But they actually were able to take some concrete changes to the levels that'll hopefully help anybody else, so yeah, the play test goes on.

It was mostly done, but some stuff in Portal 1, the final boss battle was in flux right up until near the end. We kind of had our fingers crossed in Portal 1, because the final puzzle in Portal isn't really even a puzzle, it's not very difficult, the GLaDOS boss battle. It's not an especially difficult puzzle, and before we had all of the bells and whistles in there, the final audio, it was sort of failing and failing and failing. And people said “well that was anticlimactic.” But we just knew - well we didn't know - we were hoping that if we layered enough crap on it, it would all of a sudden be more of a spectacle and people would enjoy it. But we would have been in trouble if the layering of different things hadn't turned out to be entertaining.

PC Gamer: So your approach is like, “Ah, this boss is fundamentally uninteresting so we'll just layer some crap on it and it'll be okay!”

Erik Wolpaw: Yeah! Well, it wasn't completely random, we were going from the mindset that nobody's going to want to solve a difficult puzzle while they're also being bombarded with a lot of visual stimulus and stuff to listen to. But a difficult puzzle without all this adornment isn't going to feel climactic, which we had proven that earlier by having a bunch of difficult puzzles, and people were reacting negatively to those.

And so the idea was "Here's a puzzle, we know it more or less works but people aren't finding it to be a worthy conclusion, but we know - again, hope/know - that if we put enough funny stuff in it, when there's some spectacle there that will cause it to succeed. And it did."

PC Gamer: I felt like the whole thing was building up to her breaking down. I held off putting the modules in the furnace until GLaDOS had said everything she was going to say for each one.

Erik Wolpaw: That was the one point where we kind of put some time pressure on you, in the most ham fisted way possible, we just literally had a timer counting down because that helped it be climactic. The time pressure I liked in Portal 1 was when you were riding the elevator thing into the fire, because it was time pressure but it was easily understandable time pressure. All of those lessons are folded into here. It's a little bit easier along at least some axis in Portal 2, because the team understands portals more, you can take a body of knowledge of what worked and what didn't in Portal 1 and move it forward for Portal 2.

PC Gamer: When you were starting Portal 2, were you playing around with anything fundamentally completely different?

Erik Wolpaw: Yeah, we did go down a couple of paths with some mechanics that we actually won't talk about because we might use them at some point. But one of the ideas was: what if the Portal franchise is, instead of always being about Portals – which'd be tough because it's called Portal – but what if it was always about introducing a new puzzle element that you're going through? it's about Aperture Science, and now you're going through this new testing track with this new element.

We pretty quickly found that, even though we had a couple of pretty interesting mechanics, that people would always, to a person, every play tester we had would say, “Yeah this is alright, but where's my portal gun?”

So then we went down the path of, “Well okay, what are all the things we thought of during Portal 1, and what are new things, what are new puzzle elements that combinatorially will create this much larger puzzle space?” As much as we may have been sick of portals, we found that play testers were not. They wanted more portals, and all the new puzzle elements did make it more interesting all of a sudden, between the paint stuff...

Also paint was one of the things we had played with as being “Okay this is the central mechanic: the goo.” That was one of the ones that we tried that we were actually able to fold into, and they actually played pretty well with, portals. We also went down a couple of branches where we'd take the central mechanics that we thought we were going to use as the fundamental component and try and mix it with portals. And for a lot of reasons, different mechanics - either they're just redundant, or they just ruin each other. There was all sorts of other stuff. We also didn't want it to be a game where I have a portal gun for half the game, and then this other thing for half the game.

Josh Weier: Plus I think Portal had this real elegance, where it was just: "I have my portal gun, and everything is dripping from that," And we didn't want to lose that, right? We felt that was important, players understood it and we wanted to find ways to make you and your portals more powerful, but in ways that were really obvious to people.

PC Gamer: So at one point you had the paint as being the central thing?

Erik Wolpaw: I think briefly we tried it. We tried everything. I think we had the Gravity Gun as the central thing at one point.

PC Gamer: The paint thing came from Tag: The Power of Paint , right? (A prototype by DigiPen students, just as Portal's precursor Narbacular Drop once was.)

Erik Wolpaw: Yeah, Tag, those guys, we hired them, they're all sitting in the room now. They had been off doing their own thing, working on some stuff, and then they worked on how to combine portals, and they came back to us with some maps and- "Wow, this really works."

Josh Weier: And it was a funny thing, too, because those guys were inspired by the first DigiPen students who made Portal, so they were inspired by Portal and were able to inspire us.

PC Gamer: I bet some people are working really hard at DigiPen right now.

Erik Wolpaw: It's tough to think up a new central puzzle mechanic.

PC Gamer: You guys have shown off the bouncy paint and the speed paint. In Tag, for me, the really interesting bit was when you got the sticky paint. (It allowed you to walk on painted walls and ceilings). Is that going to be in Portal 2?

Erik Wolpaw: It's up in the air at this point. Can we talk about that?

Josh Weier: We'll leave some surprises for down the road. Like everything, we test it all, we see what works and what doesn't. We're still in the process of poking a couple of things to see what we can do with paint, and some other stuff that people haven't seen in Tag that makes it all the more fun.

PC Gamer: But there are more kinds of paint than we've seen, right?

Erik Wolpaw: Yes. Sticky paint's a... we're working on it. We're working on sticky paint.

PC Gamer: This is something my friend Tom said, but we think it's a huge missed opportunity that they're called Propulsion Gel and Repulsion Gel, when they could be called Propulsion Emulsion and Repulsion Emulsion.

Erik Wolpaw: They may still be, by the time it ships, because of that. Propulsion Gel… Emulsion. Emulsion is a good word. Right. Maybe we'll take that. It's not set in stone yet.

PC Gamer: And the sticky one could be Compulsion Emulsion.

Erik Wolpaw: Oh yeah! The unknown paint may be harder to fit into that naming structure.

PC Gamer: Something a bunch of people have commented on, from seeing the videos, is that they're scared it'll be too hard for them.

Erik Wolpaw: So, it won't be. This may be more the fault of the trailer. It's hard to get someone pumped up by someone slowly and deliberately solving a puzzle. There's a panic that sets in that we're going to have to show this in an auditorium full of people, and they're not going to want to watch somebody solve a puzzle.

So the way we thought about it when we were putting it together: in the very original Portal trailer there was this sort of 2D graphic that showed it going crazy, and we thought, "Let's just show it going crazy in the game, but in-game." And it was a hard thing to split the difference.

But rest assured, absolutely, the number one goal is to have a gradual training arc, and also to ensure that things aren't too execution heavy. The person we had doing it was doing it in the flashiest way humanly possible.

PC Gamer: Was it Jeep [Barnett, Portal 1 designer and portal ninja] by any chance?

Josh Weier: I think Jeep helped us in a couple of them. We've got some other portal ninjas, too.

Erik Wolpaw: It took a lot of takes, everybody was just sitting around that night, just, you know, "Who can do the one that looks really good?" It was a long night of recording.

Josh Weier: But again, our play test process is what helped us to get through that stuff, right? Like, we put all sorts of people through just to make sure that we're not excluding anybody who could have fun with the game, because it is such a broad reaching game. It's not the typical sort of game where, you know, your girlfriend or wife or kids might look at it and go, “Ah, I don't know.” We really want to appeal to those people too, and it's the kind of game where you can do that.

My play time with Portal 2's co-op mode has convinced me it's the way a Portal game should be played. Solving the puzzles feels like planning a heist: assigning duties, calculating timing, then blundering into action and restrategising as you go. When it goes wrong, it's hilarious. And when it goes right, it's sublime.

Tomorrow I'll be talking to Gabe Newell and co about their plans to expand their games into other mediums, and handle it all themselves: including the Half-Life movie, if people want it. The trailer above is the first time we've really seen their burgeoning movie-making talents applied to Portal, and it probably won't be the last.

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