One by one, the tables recede slowly into the boardwalk. Seconds later, the trees do the same. The lights flick off, then on again, and as the water drains from the “ocean,” you realize that the sunny sky was just a projection; you’re a prisoner some kind of huge, soundstage-like room. As you watch this helplessly, the walls suddenly close in, leaving you trapped in a tiny, transparent cube. This cube is then pulled through a doorway by some kind of armature, into darkness.

That, as shown at the GDC panel “Creating a Sequel to a Game that Doesn’t Need One,” was the original opening for Portal 2. It seems that, in the years between Portal and its sequel, a lot got left on the cutting-room floor, and Valve writers Erik Wolpaw and Chet Faliszek were more than willing to share. Interestingly, the original vision for the sequel called for three of its most iconic things to be removed: Chell, GlaDOS, and the portals themselves.

“We decided to keep Aperture,” said Wolpaw. “Aperture Science seemed kind of like it was the foundation on which Portal was built. From a writing perspective, we thought there was sort of unlimited potential there to explore this mad funhouse of science. So, having decided to keep Aperture… we cut Chell. She got out, good luck to her. Who needs her? We cut GlaDOS. She kind of died in the end, and she had a nice little story arc; time for a new villain. And we cut portals. The name is in the title, but we figured we’d worry about that later.”

The plan, Wolpaw said, was to replace the portals with a new mechanic that had come out of Valve’s design experiments, called “F-Stop.” (And while Wolpaw described F-Stop as “sexy,” he stopped short of actually describing it, as it may be used in a future game.) The new villain, meanwhile, would be Aperture Science founder Cave Johnson, originally envisioned as a crazy Southern billionaire.

Above: One of the original concepts for Cave Johnson (left), with the final version at right

“In F-Stop Portal 2, [Johnson] was the whole show. He was the main character,” Wolpaw said. GlaDOS, meanwhile, would have appeared only as a little wheeled robot known as the Gyroscopic Liability Absolver and Disk Operating System (referred to as “Betty”). Whenever Johnson would finish explaining a test, she’d trundle out to quickly rattle off a string of legalese meant to absolve the company of any liability.

Originally, Portal 2 was also going to be a prequel. Set in the ‘80s, about 20 years before the events of Portal, it would have focused on a robot uprising at Aperture (which also involved, according to pictures Wolpaw displayed, a giant chicken running through the offices at some point). After about three months of work, the game was ready for playtests. “The constant feedback we got was that it was a lot of things, but it wasn’t Portal 2,” Wolpaw said. “So, lesson one: you don’t need to burn everything to the ground.”

Above: Bits of the 1980s Aperture concept did make it into the final Portal 2, though

GlaDOS and portals came back, but the team still didn’t see the need to revive Chell. “She’s mute, she doesn’t really have a character, she’s just kind of this physical presence that you occasionally see glimpsed through portals,” Wolpaw said, adding that, as writers, they felt her story was finished.

“We started this iteration of Portal with you waking up in the Relaxation Vault, and you were standing in front of a mirror so that you could see that you weren’t Chell,” Wolpaw said. “You were this other character we called Mel, who had blonde hair and a different-colored jumpsuit, and was pretty obviously not Chell. To a person, playtesters didn’t care… until the point where she wakes up GlaDOS, and GlaDOS does not recognize her.”

Above: This moment turned out to be far more important than the developers initially realized

It was at that point, Wolpaw said, that they realized Portal was about the intimate relationship players had with GlaDOS – and if she woke up and didn’t remember them, “it was actually a blow to the player.” So Chell went back in, too.