I’d like to pretend I’m all nonchalant about Portal, because we’ve all played its predecessor Narbacular Drop to death, and knew a Source version was coming. Or that the trailer was old hat, since Graham procured it from Valve a few days before release. Instead, I’m still watching this thing an average of five times a day. The bit I love, apart from every line of the gorgeously wonky synthetic voice-over, is the trick the player pulls in the fast montage of whacked-out nutsoness, just before the plummet through the infinite loop before the end. And it took me a long time to work out what he was doing.
Here’s the setup. The player needs to get to the X, a lower platform that’s too far for him to jump. I think he takes a rather unnecessarily complicated route, but we’ll assume some hidden rules prevent him from doing it the obvious way. He’s about to cast two portals, the first at 1 and the second at 2.
He casts 1 first, close to the platform he wants to reach, then throws himself off and casts 2 beneath him as he falls. The reason for casting 2 after jumping, as near as I can tell, is that it’s easier to know where you’re going to land once you’re in the air. Also it looks more rock.
He plummets through 2, shooting him up through 1 with all the velocity his fall has given him.
At the apex of his climb, he turns to face the place he came from – 0 – and opens a new portal there – 3. Since he’s using right mouse rather than left, this new portal replaces 2, rather than the 1 he’s just come out of.
Here we’re looking at the ground – he’s falling back toward the portal he just shot up out of, 1, and through it he can see the same view as from his starting point 0, but upside-down – note the X is now on the ceiling.
His downward velocity is translated into lateral velocity because the portals are perpendicular, and he’s flung all the way across the chasm – automatically spinning in mid-air to realign himself with gravity…
…to land on his feet at the destination. Bravo, test subject!
“At the enrichment centre, we believe a highly motivated test subject can carry out rather complex tasks while enduring the most intense pain.”