Portal: The Flash Version is a puzzle platformer game. It is based on Valve's Portal and gives you portal puzzles in 2D. The flash game is centered around the use of a portal gun, very similar to the game it is based on.
The game started as a Flash project by Valve fanboys Hen Mazolski and Ido Tal, back when Valve first announced the original Flash game. They decided to make their own version of the game as a side project, just for themselves. What they had made turned out to be a fun game to play even in 2D and they decided to publish it on the web.
The game includes 40 challenging portals thinking levels of increasing difficulty. The game is based on Valve's original game and contains many of the same elements as the original Portal game; energy balls, cubes, turrets and even the famous crusher from the trailer. The puzzles consist of using these elements to remove obstacles and reaching the exit. Although the game is in 2D, many of the principles from the original games still applies, such as the conservation of momentum.
The game also includes a console to mess around with after finishing the game. You can't get Kongregate badges while playing in Console mode.