Valve is giving away an extended demo of it’s unique puzzle game, Portal, to all Nvidia customers. If you don’t already have Steam, Valve’s game distribution software which allows users to buy and download games straight to their desktops, you’ll have to download it and allow it to scan your system to make sure you do have an Nvidia graphics card installed on your machine. Once that’s done you’ll be able to download and play Portal: First Slice.

Check out the Portal trailer:

I must warn you, the game is very intriguing. You start with basic, simple tasks and puzzles and progress to more challenging ones as the demo continues. After I played the couple demo levels l found myself really wanting to spend the $20 to download the full version. I haven’t succumbed quite yet. Also, while it wasn’t advertised, I was able to download two other Valve games for free, Half-Life 2: Deathmatch and Half-Life 2: Lost Coast. I haven’t played either yet, but I’m much more interested in Portal. Nvidia users, get your copy here.