PORTAL
INTERVIEW: KIM SMITH, DESIGNER


PCPP: How would you describe Portal? What kind of game experience are you going for?
KIM SMITH: Portal is a first-person, single-player game set in the Half-Life universe. The game mechanic is built around a Portal gun that allows you to connect two points in space. We wanted to create an isolated environment to let us explore our ideas and the portal game mechanic.

The best analogy I can think of for the Portal gun is the gravity gun in Half-Life 2. Prior to Half-Life 2, physics was mainly used in games to make things look neat, like a grenade bouncing around, but honestly didn't matter very much to a player. With HL2, the team, especially Jay Stelly, wanted to focus on how to make physics a deeply ingrained part of the player experience. Obviously, that created a bunch of technological hurdles, such as simulating player movement, or having the AI operate with physics to move NPC's. It also created a bunch of design challenges too, like how would the player actually put energy into the physics simulation, and most importantly how this would translate into something fun. The gravity gun was an amazing innovation in gameplay, I mean, who knew that physics could be so much fun and that a saw blade could have so much potential?

PCPP: What was the evolution of the game? How much of it came about after seeing Prey and thinking, we can do more with that?
KS: A little over a year ago, we were all students at DigiPen Institute of Technology. As a part of our senior year project, we created a game called Narbacular Drop, which was our first test of portal-based gameplay. Every year, DigiPen holds an expo to bring in developers to check out the senior student's game projects. A couple guys from Valve came in, took a look at Narbacular Drop, and invited us to stop by and show our game to Gabe Newell. Gabe watched our demo, and within fifteen minutes offered us a job on the spot to make what's now called Portal. As far as Prey goes, when we started Narbacular Drop we had no idea that the game existed. After all, I think we were all about 13 or so when Prey was first announced back in the late nineties.

PCPP: How much of Portal's design is based on showing off the potential of the Source engine?
KS: Actually, when we created Narbacular Drop, we used an engine that we programmed ourselves and was designed around the fact that we were going to be dynamically cutting holes in our geometry. After coming to Valve we moved to the Source engine, which gave us a huge amount of resources to start with: tons of debugging utilities, a huge math library, great content creation tools, etc. Some work was required to enable physics through portals, which made for an interesting test of Source's modularity.

PCPP: The presentation of the game with the computerised voice and surreal instruction is very usual, why did you decide to go that way? How does it capture the feel of the game?
KS: In Portal you play as a test subject for the Aperture Science Laboratories, and the computer voice is there to remind you that you are always being studied, like a rat in a maze. The game mechanic in Portal is a very abstract and unique concept and we felt the environment the player is in should reflect that.

PCPP: How much should we think of this as a cool mini-game, and how much should we look at it as a test for things to come?
KS: A bit of both really, Portal is an attempt to explore a specific type of game mechanic, but it’s also a game with its own unique place in the Half-Life universe. We’re really excited to see how our customers receive Portal, and move forward based on what kind of reactions we get.

PCPP: What is the most fun you've had designing levels and playing around with the portal technology?
KS: Honestly, the most fun for me is watching our weekly play tests and seeing all of the different ways people will tackle and solve a challenge. We're constantly amazed by the solutions our testers come up with that we had never thought of before.