Based on Valve's Portal, Portal: The Flash Version brings it all up in 2d!
Portal: The Flash Version includes over 40 challenging, portals thinking levels, and everything's included, in 2d - energy balls, cubes, turrets and even the famous crusher from the trailer. The game also includes a console to mess around with after finishing the game, or just being frustrated by thinking with portals!

  Some history:
Portal: The Flash Version started as a Flash project by Hen Mazolski and Ido Tal, back when Valve first announced about their exciting new game. We define ourselves as definite Valve fanboys, and we just couldn't wait to play the game.
We decided to make our own version of it ourselves, just for us, as a side project. Little did we know, it turned out to be a very fun game to play even in 2D, and after some pressure from our close friends, we decided to send it out to the world. This is the result.

  Game Controls:
Left mouse button - launch a portal.
A W D - movement
Q - launch a blue portal.
E - launch a yellow portal.
R - Close both portals.
F - pick up an object.
~ - open up console (enable through the options)
O - quick quality adjust.
Esc/P - pause game.

» Flash Player 8 and up
» Flash Player Global Storage 10kb
» Game resolution 800x450
Portal: TFV Forum | Video walkthrough | We Create Stuff | Valve's Portal :)