After I figured out that the game wasn't a Myst-esque point-and-click puzzle, the riddles became a whole lot of fun. I'll definitely be coming back to this one for a while.
A somewhat related site:
http://www.99rooms.com
Not nearly as hard as this one, but then again, it's meant to be more artistic.
BTW, was the solution for level 2 just to type in "level 3" in the URL? Because that's how I solved it...