The Sourceruns team have completed a 8:31.93 run of Portal, which is absolutely ridiculous, brilliantly devious and laudably investigative. The latter descriptor is appropriate because of the level of understanding required to complete the run. These glitch-hunters have an in depth knowledge of each chamber, of the Source engine and of the strange ways in which portals work. You can watch the run below, and read about the techniques used and the analysis of each chamber in an extensive document. Oddly, the closest I think I’ve ever come to exploring a game in this way was when I played deathmatch Doom for an entire year without stopping. I knew every layout and every trick, and I was still rubbish.