The innovative first-person-puzzle emanating from Valve’s Orange Box is getting a free, extended demo, but to run it you’ll need (you guessed it…) an Nvidia graphics chip.

Dubbed Portal: First Slice, the “special demo” will be compatible only with Nvidia-powered PCs, leaving ATI fans salivating. In order to download it, please visit this page. The site will automatically scan your PC for any Nvidia video card you might have installed (plus the additional drivers) and afterwards your access through the Portal will be granted. However, be advised that although it offers a bit more gameplay than the initial demo, it doesn’t bring anything new, so if you’ve already played the entire Portal on your PC, Xbox 360 or PlayStation 3, you can abstain…

Valve is not satisfied though with seeing its customers leave, so, following the patented model of bundling lots of goodies in the same (Orange) pack, it has also included Half Life 2: Lost Coast (a tech demo from a few years ago showing off Source engine’s HDR capabilities), Peggle Extreme and Half Life 2 Deathmatch (a multiplayer module based on Half Life 2) in the free download. Moreover, Valve announced that Nvidia will include a link towards Portal and the other games, every time someone downloads Nvidia drivers.

According to the Washington-based gaming giant, this is just the beginning of a long-lasting, beautiful friendship. Future plans also include distribution and development agreements between the two companies and sponsorship for Counter-Strike and Team Fortress 2 competitions.