The documentation contains a few distracting typos.
Use of blue for text in the HTML is distracting—blue is generally considered a link but not in the Megahedron HTML pages. On some pages, black text is a link. It's distracting, but not a real problem.
The HTML used different background colors—in some places it's a sort of light peach or wheat, in others it's white. Again, this is distracting.
Uses a right handed coordinate system—for someone used to POV or BMRT this could take a little getting used to. Also, the coordinate system is rotated 180 degrees in the Y direction and 90 degrees in the X direction, which puts the Y-axis into the screen and the Z-axis up (X is to the right). This difference from POV/BMRT is immediately obvious when trying to interpret the lighting examples used in the tutorial.
File format uses curly braces ({}) for comments.
Sample images are not very impressive. They tend to show modeling features more than the rendering capabilities.
No mention of radiosity or displacement mapping support.