GlaDOS was added to Portal because playtesters kept asking 'When does the game start?'
"And we were all like, 'Man, this is the game!?'"
Weekly digests, tales from the communities you love, and more
You are now subscribed
Your newsletter sign-up was successful
Want to add more newsletters?
Every Friday
GamesRadar+
Your weekly update on everything you could ever want to know about the games you already love, games we know you're going to love in the near future, and tales from the communities that surround them.
Every Thursday
GTA 6 O'clock
Our special GTA 6 newsletter, with breaking news, insider info, and rumor analysis from the award-winning GTA 6 O'clock experts.
Every Friday
Knowledge
From the creators of Edge: A weekly videogame industry newsletter with analysis from expert writers, guidance from professionals, and insight into what's on the horizon.
Every Thursday
The Setup
Hardware nerds unite, sign up to our free tech newsletter for a weekly digest of the hottest new tech, the latest gadgets on the test bench, and much more.
Every Wednesday
Switch 2 Spotlight
Sign up to our new Switch 2 newsletter, where we bring you the latest talking points on Nintendo's new console each week, bring you up to date on the news, and recommend what games to play.
Every Saturday
The Watchlist
Subscribe for a weekly digest of the movie and TV news that matters, direct to your inbox. From first-look trailers, interviews, reviews and explainers, we've got you covered.
Once a month
SFX
Get sneak previews, exclusive competitions and details of special events each month!
Portal's GLaDOS is one of the most memorable villains of all time, but would you believe Valve only added her in to make people realize they weren't just playing an extended tutorial?
We came so close to a world without the casually murderous artificial intelligence, and we only found out about it now thanks to an interview with Valve game designer Robin Walker. GR sister site TechRadar spoke with Walker in a wide-ranging interview and recently shared his explanation of how GLaDOS narrowly came to be after playtesters kept coming back with the same question.
"GLaDOS didn't exist then – it was just 'the game'," Walker explained. "And I remember we had playtesters come in and they would have a lot of fun and I remember more than one of them would finish and, essentially, in their feedback say, 'All this training stuff was really fun but, like when's the game start?' And we were all like, 'Man, this is the game!?' Like, what makes someone go through that experience of those levels and come out and ask where's the game start? What are the cues they are looking for that make them believe this is the game?"
Before you barely avoid death by incinerator and begin to roam behind the walls of the Aperture Science Enrichment Center, Portal's stages all feel sterile and disconnected, progressing only in terms of the mechanics you need to use to solve their puzzles. Without GLaDOS' increasingly transparent distaste for you and everything you represent, it honestly would have some tutorial or "Challenge Pack DLC No. 3" vibes.
"And so GLaDOS came out of that, this sort of set of theories we had – [the players] have to believe that there's a purpose for all this learning, that there needs to be some kind of antagonist, there needs to be some threat, some force, something that makes it look like it's going to push back," Walker said. "That maybe there needs to be some concept of what failure can be for the gamer."
Valve is working on more games after Half-Life: Alyx, but it isn't ready to announce them yet.
Weekly digests, tales from the communities you love, and more

I got a BA in journalism from Central Michigan University - though the best education I received there was from CM Life, its student-run newspaper. Long before that, I started pursuing my degree in video games by bugging my older brother to let me play Zelda on the Super Nintendo. I've previously been a news intern for GameSpot, a news writer for CVG, and was formerly a staff writer at GamesRadar+.


