Going to their website and watching their videos that aren't compressed to youtube standards. There isn't any lag in their tech demos. Their only real issue currently seems to be getting shadows right.
Shadows are simplistic, no hint of reflection, refraction, multiple lighting, light sources(Only seems to have a single-direction sun)...
I don't know how they get away with reflections and lighting without some ray tracing involved.
All of those reflections were a single horizontal plane, and thus they can easly cheat by duplicating the scene along the plane. In fact, I think they mentioned it when talking about how many points it was calculating for.
Bottom line:
Probably plenty of FAKE.
Could probably be beat by a combination of a polygon-based system for finding the polygons, and then having it recurse into a subsystem that procedurally generates fine details like a curve of a tree, the shagginess of the trunk, a surface texture(like a current bump map, only more detailed, and generated as needed by vague parameters. Trades precision(exactly what the artist made) for detail.
Also, seen 3D modeling programs? Seen how you can create a camera flythrough in a no-textured, low-detail, technical view, hit "render", and come back a while(minutes, hours, days) later with a "real time" version in full detail?
What I am inferring is that, until a downloadable program comes out that allows the user to make their own levels, what is the diffrence between a falsified framerate and a realtime recording after it has been uploaded to youtube?
Oh, and one more thing: Size.
Did they ever show a vast landscape, stretching beyond view over the horizon?
I suspect that they can't while retaining the accuracy and details of their system, if a true system it is.
Now, despite all that, I would be delighted to be proven wrong with a mindblowing interactive downloadable example, but until/unless that happens, I will remain pessimistic.