Fun Portal fact: it's based on a game called "Narbacular Drop", which, aside from having one of the weirdest title in gaming history, really doesn't resemble Portal a whole lot except for the core gameplay mechanic. Specifically, the whole story about participating in a series of tests in a laboratory isn't there, instead it's about a princess defeating a demon. I know, boring right? The Aperture Science facility sounds so much more riveting.

We've also got Portal 2 and both Portals at once on tap here.