As Valve releases an update of Portal
for Xbox Live Arcade, Gamasutra presents an article written by the game's creators
and reprinted from Game Developer magazine, discussing the genesis of the 'Game Of The Year'-winning cerebral action-puzzler.
Though early and constant playtesting enabled Portal's development team to refine the game's difficulty and experience, the group also found that it needed to add "flavor and an entertaining narrative" to keep player's attention beyond fifteen to thirty minutes into the game.
They brought in Valve staff writer Erik Wolpaw to help shape Portal's
story around one of its huge restrictions:
"Practically speaking, we didn't have sufficient time or staffing to add any human characters, which would have required an impressive amount of animation work and scene choreography. That meant the story had to be expressed without the benefit of any visible extra characters.
A week after the meeting, Erik came back with some sample dialog he'd recorded using a text-to-speech program. It was a series of announcements that played over the newly-christened "relaxation vault" that appears in Portal's first room.
Everyone on the team liked the funny, sinister tone of the writing, and so Erik continued to write and record announcements for other chambers, while still searching for the story proper."
The team found that the announcements gave playtesters an incentive to keep playing and also provided a narrative, albeit sometimes menacing voice for the game:
"The guide, now named GLaDOS, would simply talk to players throughout their experience -- praising them, taunting them, and, whenever possible, trying to make them feel guilty for the nonstop acts of defiance and mayhem that game players are conditioned to commit routinely in game environments.
Our hope was that by the end of the Portal, players would know GLaDOS better than any boss monster in the history of gaming. Though we knew at some point the player would have to meet and destroy her, we thought it would be even more satisfying if players got a chance to cause her some emotional pain along the way.
What started out as a seemingly burdensome constraint -- a total lack of human NPCs -- eventually turned into one of the strongest parts of the game. Navigating the environment is Portal's primary gameplay challenge; In effect, the environment is your enemy. GLaDOS's disembodied omnipresence gives that enemy a voice and personality."
You can read the full feature
, which describes how Valve hired Portal's
team straight after they graduated from DigiPen and how the group playtested the game (no registration required, please feel free to link to this feature from other websites).