Portal is one of the best video games of all time, but its origin story shows just how contingent that success was.
Portal's development history is charted in the video below, progressing from the original Narbacular Drop through a bunch of recycled Half-life assets, an almost steampunk appearance and finally the clean look we know and love.
While the history of Portal from student project to surprise smash hit of The Orange Box is no secret, the Valve News Network team has done a great job collating publicly known information with behind the scenes material and never-before-seen assets.
The result is fascinating, and a great example of why we all set our watches to Valve Time; the months (years!) of polishing paid off, adding an iconic aesthetic and one of gaming's most loved narratives to solid puzzle and gameplay design.
The team's efforts in making the game readable and memorable turned Portal into a classic. You may now have an inkling of why Half-life 3 is taking so long.