Portal is pure contradiction. It's a character-piece in which you meet no characters. It forces you into complete mastery of your physical form but you can't see your own legs.
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And by a good few hours it's the slimmest component of the gargantuan Orange Box, yet it's the one that's most stuck with gamers around the world. And it's the best. It's also a hard sell.
Tell us you've never played Portal and we'll explain the game's unique charms. It'll be easier if you haven't. You ready? Listen.
There's this game, right, from the Half-Life lot, where you play a mute girl and... no, it's not like Half-Life. There're no guns. Okay, one gun, but it's not a gun. It's a gun that fires holes, and it's not actually a gun... it's called the portal gun.
Well, it's called the Aperture Science Handheld Portal Device, but it's a thing that fi res a small disc you can connect two points with and move between them but... no there aren't any bullets and...
The portals are doors, but they're also holes, and windows, and chutes. The simplest interaction is obvious: put a portal on a wall next to you, put another on the far side of a wall you can't jump over, and step through.
That's the easy bit, the bit you'll do instinctively because you're not a cat that gets startled by its own reflection. It gets tougher when you're falling at terminal velocity in an infinite floor/ceiling loop, or when you need to calculate the exact spot to hurl your second portal in order to gain maximum momentum so you can fling yourself over a pit of lethal goo - while soaring twenty feet in the air. Actually then, then you do start to feel like that cat.
You must use your not-actually-a-gun to get around the game's world. That world is better thought-out, more complete and better presented than most of its peers, despite being built almost exclusively of white, featureless corridors and pools of toxic sludge.
Somehow, with a handful of strong visual elements, Portal manages to make a habitat both more believable and more alien than games that span entire galaxies.
Portal's chambers are ostensibly bland and sterile, but they have their cracks. Peek behind the curtain, peer behind a smashed wall-panel and you see the dirt and grime of the real world beyond.
One side of the divide is otherworldly and robotic; the other is filthy and human. Do you see why both need each other? There's no narration, no clumsy exposition emanating from the main character's brain, but within moments you know why you're in this bleak tank.
It's not for love, or glory, or because you woke up in a village during a harvest festival and now you've got to go on a big quest. It's for survival. It's nothing more than a complicated rat maze, stripped of the tasty cheese at the centre (though that's replaced with cake. Maybe. Famously).
The cheese/cake here is life, and the scientist conducting the experiment is completely insane. Well, she's not insane. She's rational and perfectly lucid. But she's also utterly batshit mental, and forces you through trials that would break most humans - both physically and mentally.
She's called GlaDOS, and she's a robot. She's also one of the most human characters ever to grace a game, and manages - despite being nothing more than a set of personalities, hung like baubles around a white plastic tree - to become completely sympathetic.