I like the way the color-coded statistics blocks get assigned to slightly differently named versions of the monster - the Bloody Gnomes, Sadistic Hobs, and Redcaps are all the same guys, but... are they? Nice!
This does quite a lot with quite a little. I feel confident that it would make a perilous, interesting few evenings of Wooded Confinement for the PCs, and that's so inspiring to find in so few pages.