This is a Loop of Death puzzle, a unique type. Almost all of your favorite (and unfavorite) loop puzzles have been combined into a single type. Detailed rules, along with an example, follow below the image and comments.
(Click for larger size
3/20/2011 5:22 AM ET – Fixed a goof in the far bottom right corner that resulted in no solutions by a minor change to the regions. You probably found this contradiction if you made any progress at all in that area. My apologies.
As far as my marathons/unique puzzles go, my guess is this is probably tied for the easiest – size has something to do with that – but I could be completely off in either direction. Of course, this still means it is going to be really hard.
Grid size is 29 by 29 squares. This means 30 by 30 for the vertex clues, although I never used any of the edges. From that, I’m sure some of you are going to figure out what puzzle I paid homage to in constructing this one, but I’ll leave to you all to guess.