"That's cute music. Where am I? How do I move?"

"Use these keys - w, a, s, d. You can jump with the spacebar. They're giving you time to figure it out. This is a 'relaxation vault'."

He follows the instructions then starts jumping and walking around randomly. "Can I do anything with there? Oh I can," he says, when he manages to hold a clipboard. "Weird symbols. What's the timer?—ooh robot voice, hi robot."

"Yep, that's GLADoS. The AI."

"An actual AI or just a, you know, bunch of interactive reco—ooh portal! I can see myself! What's that on my legs?"

"Just recordings, alas. Or fortunately, depending on your perspective. They're your long fall boots! A way for the game to explain away why you don't break your legs running and jumping around with portals,"

"...that makes no sense," he says, but goes through the portal and starts exploring.

"So, the idea of the first few puzzles is just to get you used to things - and used to the atmosphere." Here is a room with a cube and a pressure plate and a door with a string of lights going from the plate to the door.

"Cube and button based testing is an important part of the Aperture Science Enrichment Center Testing Process." 

"...Like that."

—that startles a giggle out of him. "Cubes and buttons, alright, I think I can manage that."

Cube and button!

The creepy narration continues. Something about 'a rare side effect of the material emancipation grid may accidentally emancipate your teeth and/or skull'.

The next room has him traverse portals that change on a timer to get a cube to a button and then out the door, even past glass walls. "Notice how they made sure the first thing you see in this room is the door - and the second thing is the fact that the portals are changing? It's leading you without actually saying 'use the portal'. That's good tutorial design right there."

"Is it? What's bad tutorial design?" he says, following the cues.

"The example that comes to mind is giving the player a wall of text they have to read, and explaining all the controls one after another, and then expecting them to know what to do and never explaining it again and suddenly your character starves and you don't remember that it mentioned in one sentence in the page of text you skimmed that you need to eat and you get frustrated and never touch the stupid game again."

It sounds like something that happened to him.

"Bad experience?" he guesses. Success at chamber! "This is pretty intuitive," he adds.

"Yep. And yeah, Portal is very, very good at it!"

The next chamber gives him the portal gun! He can aim the orange side of the portal, the blue side is stuck to a wall.

The cube is on the floor in a small pit.

"Do I ever get to control both portals?" he wonders, taking to the controls like a natural.

"Yeah, but later. They're getting you used to things by stages - the puzzles get harder and harder. It's good. I shouldn't tell you the big twist. There's supposed to be a sequel out soonish, Portal 2, I'm pretty excited for it."

"Oh, there's a plot? I thought the atmosphere was just decoration." Next chamber!

"Yes, there is a plot."

"...Please continue testing at your own pace. There will be celebratory cake at the end of the test."

Terry snorts and mutters too far under his breath to be understood, "The cake is a lie."

"What was that?" he asks as he proceeds.

"Something that would spoil the story if I said it louder. Sorry."

He giggles and proceeds. "This is slightly ominous in a somewhat funny way. I like this game."

Terry is only slightly tempted to tell Sadde the solutions to the puzzles. The first really frustrating one - involving leapfrogging from place to place by moving both portals - he lets on a subtle hint though.

Sadde takes the hint but normally doesn't need them. His spatial awareness seems really good, even in-game, and he gets the hang of it pretty quickly. He is also very amused by the "recordings" and provides commentary.

"Did she just say I was going to be baked?" he asks, giggling horrifiedly.

"That is what she said, yes."

"Oh my gosh this is so creepy," he says, giggling more.

He will continue delightedly playing for a while if Terry doesn't stop him.