While the Half-Life series may be seen as the complete antithesis of what people think of as an "adventure" game with it's weaponry and reflex shooting and dying-and-reloading, their Source Engine brings one of the most intriguing and fun to play action-adventure games ever, Portal.

So you're a test subject in the sterile white labyrinth of Aperture Science, where you are to run an impossible eighteen-level obstacle course.  Luckily you get to use an invention that costs more than your hometown; the Aperture Science Handheld Portal Device.  You fire two portals, orange and blue, creating a wormhole you can see through and through which you and objects can move, retaining all forward momentum.  You can only create portals on flat, unmoving, hard surfaces, basically concrete and tile.  You can create an infinite mirror in a hallway, or fall endlessly and continuously from the ceiling to the floor until you've had enough.  Any forward momentum a mass has is retained through portals and this is key to manipulating the environment to cross impossible chasms and accomplish superhuman feats.

Supervising and encouraging you along the way is GlaDOS, a computerized A.I. who cheerfully spouts amusing facts and figures about you and the achievements of Aperture Science.  You'll get cake at the end.  Can't reach a box you need to weight down a giant button?  Shoot a portal over the button and another under the box and it falls through the ceiling.  Using the portals as a mirror you can see you are a girl in an orange jumpsuit with spring-heel devices on her feet; you can't die from falling.  You can die if you hit water or get shot by gun turrets (Wait...gun turrets?) or the inevitable mishap when redirecting slow-moving energy balls fired from giant industrial equipment.  You'll need to ricochet and bounce those around to activate machinery, just don't get hit.  By the time the game gets hard, you know how to deal with things.  Yes, it's not quite a safe testing environment at Apertur e Science--none of the frosted glass observation windows show signs of life and GlaDOS weirdly decides to detour you through some military testing chambers which are definitely not on your schedule. 

The best way to describe the tone of this game would be to imagine if Douglas Adams wrote System Shock. There's a menacing breeziness to it, and the portal gun is so much fun to play with I can't wait for more of this plot arc (which takes place in the Half-Life universe) to unfold. GlaDOS will go down in history as one of the classic memorable antagonists, and I must single out the brilliant voice work along with the writing in this game as a big part of this. 

Portal is short but satisfying. Completing the game unlocks more difficult versions of the test chambers and the player can compete for quickest time or fewest portals used. Don't let the platformey-twitch aura fool you; the controls are responsive and you never feel that the designers are attempting to overload your physical dexterity.  The learning curve is gradual, and it is satisfying to eventually figure out how to take a flinging acrobatic fall across a chamber, fire a portal, then tumble out of control, land on what was the wall before, flip upright and realize you made it where you need to be!  By default the physics engine "funnels" you into a portal you're falling toward -- there's an option to turn this off in the settings, but I can't imagine why you would.  By the time the weird physics work their way into your brain, you can deal with the dreaded Unstationary Scaffold and be awarded w ith a Victory Lift. With practice you'll soon be flinging yourself through some disorienting and acrobatic aerial stunts, and outwitting what has to be the world's daintiest gun turrets. 

You can purchase and download Portal for PC through Steam, or it comes packed along with four other games on PC and Xbox 360 in The Orange Box. I played the 360 version which had optional developers commentary which is almost a de-facto built in walkthrough.

System Requirements:

• 1.7 GHz processor
• 512 MB RAM
• DirectX 8 compatible video card
• Windows 2000/XP/Vista