i love flash sites and this one is interesting, but i defiantly agree with the accessibility comment, which is odd, because i feel that interaction, especially when its a highly immersive and exploratory experience, leaves a much more vibrant and notable mark than more static sites. i think also one other thing to point out, interaction removed completely, is that this site is very well designed visually (which is where most people fail IMO).
a quick break down of simple tricks.
- uses flashes drawing API
- mimics 3d using scale, rotation and color.
- sound architecture also aides into tricking you into depth (though i feel the pencil sounds are a bit random)