There's a new way to access that content, however. It will be available on PS3 later this year, thanks to an upcoming patch which will add PlayStation Move support to Valve's critically acclaimed puzzle shooter.
The free title update will add Move support for the entire game, letting you aim and shoot with mouse-like speed. Adorably, the orb on the Move controller will dynamically change color to match the color of the portal your gun will shoot.
On top of the title update, Sixense is also adapting their MotionPack DLC for distribution over the PlayStation Network. Unlike the patch, this will be a paid offering--although Sixense hasn't figured out a price yet. These challenge maps will showcase more of the Move's functionality. In addition to being able to aim, the game will track the 3D movement of the motion controller. You'll be able to pick up boxes, for example, and place them far away by moving your controller closer to the TV. You'll also be able to rotate the angle of portals, and perform other tricks unavailable in the main campaign. This video shows off how the Hydra was used, but it functions identically with the Move: