Portal's success made its clever references and in-jokes part of the gamer lexicon -- but memes and humor weren't what made Portal so successful. It was because of the relationship story it told, says writer Erik Wolpaw.
"That is a focus that we want to keep," he tells Gamasutra, as part of a new feature on Valve's development of Portal 2. "...Despite being a game it told this intimate story about your relationship with this one other character."
"Even though we want to introduce a few new characters, we want to keep the core piece of the story as your relationship with GLaDOS, and how that’s changed by what you did in Portal, and then have some place to go as the events of Portal 2 unfold," he says.
Portal 2 poses its creators a significant challenge -- how do you top something that so quickly became a beloved surprise hit? But Wolpaw says the secret to Portal's success was that nobody set out with the goal of smashing expectations.
"It’s always a challenge," he tells Gamasutra. "The best way to deal with it is to power through and just do something that is going to be good. If you set yourself up to think, 'It's gotta be revolutionary!' you’ll probably just make yourself crazy and never finish it."
"We had a bunch of ideas left over from Portal, and we had a bigger team that we could put to work on it, we definitely have a lot of new puzzle elements, and the paint stuff turned out well," he explains. "Everything’s looking good. You just try and make the best game you can."
Yep, the relationship between Chell and the Weighted Companion Cube is one I'll never forget.