[Stares down-page in faint terror.] What a lot of arguments we're going to have today. So, for those of you currently visiting us in search of gaming rather than debating, hopefully this will do the trick.
The chaps behind the splendid Flash version of Portal have generously converted their 2D maps into 3D versions for Portal-actual. All 40 of them. At three and a half hours of happy puzzle-solving, this mega-pack is pretty much equivalent to Portal itself in terms of length. In terms of quality? You tell me.