portal prelude?

anyone know anything about this 'portal prelude'? it seems to be a mod for portal. anyone try it? it looks really cool!

here's the link to the website: http://www.portalprelude.com

here's a link to a video clip: http://www.gametrailers.com/player/40078.html

Portal Prelude was released . . .Today! It's a free singleplayer prequel mod to the happenings in Portal. Here's a review.

Downloading now (it's 775mb)

Portal: Prelude, as its name states it, is an unofficial prequel to the game Portal. Its story revolves around the pre-GlaDOS epoch, even before she was plugged in. At this time, test subjects were monitored by real Aperture Science employees whose work was tedious, lengthy and repetitive. This is why they decided to build a great artificial intelligence that could both replace them in these difficult tasks, but also take responsibility for many other tasks within the complex and compete with Black Mesa's superiority. All employees of the Aperture Science complex are now eagerly awaiting GlaDOS. Maybe even a little too eagerly, as the upcoming events will tell...