Just as predicted a few days ago, Valve Software, has made their classic Portal and Half-Life 2 games available for the NVIDIA Shield. There's no word on if the games will be ported to any other devices. Although it is obvious they will work on Android, it's possible that the only Android hardware capable of running these games effectively is the Shield. Of course, it's actually more probable that NVIDIA secured an exclusive deal for now. Maybe the games will come to other Android devices which are just as capable as the Shield.

Both games are on the Google Play Store for $9.99 each. This is the same price you pay for both games on the PC as well, which is where they originated. Here are a couple of quotes from the Play Store describing each game,

Portal Description -

As featured in TegraZone and winner of over 70 industry awards and 95% MetaCritic score, Portal is available on NVIDIA SHIELD.

Portal is a hybrid of FPS and puzzle style gaming that creates a new genre of spatial brain teasers, offering hours of totally unique gameplay. Set in the mysterious Aperture Science Laboratories and noted for its humorous writing, the game requires player to solve puzzles and challenges by opening portals, maneuvering objects, and moving themselves through space in ways that used to be impossible.

Playing Portal today will teach you how to love a "companion cube", whether a computer named GLaDOS really wants you dead, and why your friends keep telling you
"The cake is a lie".

Half-Life 2 Description -

As featured in TegraZone and with over 50 Game of the Year Awards and a the highest MetaCritic score of any PC game, Half-Life 2 is one of the most celebrated and best selling games of all time.

Winner of multiple Game of the Decade Awards, Half-Life 2 offers a startling level of realism and responsiveness, opening the door to a world where the player’s presence affects everything around him, from the physical environments to the behaviors – even the emotions – of both friends and enemies.
The player again picks up the crowbar of research scientist Gordon Freeman, who finds himself on an alien-infested Earth being picked to the bone, its resources depleted, its populace dwindling.

• Digital Actors: Experience the most sophisticated in-game characters ever witnessed.

• Advanced AI: Friends and foes assess threats and fashion weapons from what is at hand.

• Stunning Graphics: Incredibly realistic environments and special effects.

• Physical Gameplay: Objects obey the laws of gravity, friction, and buoyancy.

Sound off if you are intrigued to try these games out on the Shield.

Source: Google Play Store - Portal & Half-Life 2