GDC 2012: How Portal 2 Was Made


The list of things Valve was prepared to jettison while making Portal 2 is enough to make series fans feel faint: Chell. GLaDOS. Portals. In a free-wheeling and often hilarious panel, Valve designers Chet Falisek and Erik Wolpaw took a rapt audience step-by-step through the game‘s design process.

The idea of moving forward without GLaDOS exemplifies the disconnect between studios and their audiences. Valve had lived with the passive-aggressive robot for months — gamers only for hours. Still, the initial design concept seems bizarre in retrospect. Players were to be given control of a mechanic called “F-Stop,” which is still a guarded secret, in case Valve want to use it in the future.

Cave Johnson was initially conceived as the main antagonist, with GLaDOS limited to a cameo role as “Betty” a small, wheeled robot who would occasionally show up to deliver comedic, rapid-fire disclaimers before tests began. Falisek and Wolpaw showed off a rough version of the intro sequence for this ur-version of Portal 2, which features what looks like an idyllic tropical island, until it turns out to be just another Aperture prison cell.

Thankfully for Portal fans, this version was quickly scrapped, and portals, Chell, and GlaDOS were brought back in their original forms. Valve learned their first lesson about making a Portal sequel: “don’t burn everything to the ground.”

In the time between Portal 1 and Portal 2, Valve had hired developers from the team that made Tag: The Power of Paint. Initially set to work on Left 4 Dead, they were subsequently drafted into the Portal 2 team, taking responsibility for the game’s various gel mechanics. Mechanics, in general, were a challenge. The design team had to introduce old mechanics to new players without boring old ones, while simultaneously refining and perfecting what they had.

Re-examining old gameplay led to clever new solutions. The automatic Portal-switching in the early “carousel” puzzles (designed to introduce the portal mechanics) became button-activated, which reduced confusion. The plasma ball was replaced by lasers, which had similar qualities, without the knack for sneaking up on players from behind. In sequels, Wolpaw argued, there’s no need to be a slave to the original — “if you’re improving it, players won’t care.”


Wheatley was obviously the most important change, and therefore the greatest challenge. The plummy robot had immediate utility — he established a humorous tone right off the bat, and provided a burst of exposition. Nevertheless, the developers initially planned to have GLaDOS kill him off and introduce players to six subsequent spheres, each with a distinct personality. One, a “Morgan Freeman” robot with an specific store of folky wisdom (only relevant to the 20′ x 20′ room he inhabits) is a character that all gamers will regret missing.

This approach didn’t work, but the designers so loved GLaDOS’ murderous moment they decided to simply kill Wheatley and then bring him back. They were similarly stubborn about another gag, in which a player drops Wheatley down a flight of stairs. For this to work, players had to be able to drop him, and if this were possible, the developers had to ensure that each level was carefully gated so that players couldn’t accidentally leave Wheatley behind. This proved so complicated that the staircase joke was eventually excised.

Wheatley’s voice was originally provided in temporary form by Valve artist Richard Lord, who is bizarrely still in demand among a cult group of Portal 2 fans. Stephen Merchant proved a better option — his rapid-fire delivery was good for delivering exposition efficiently, and his comic timing and improvised dialogue provided extra hilarity.

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1 Comment on GDC 2012: How Portal 2 Was Made


On March 9, 2012 at 1:30 pm

Awesome article , need more of these