Though, ah. I'm not entire sure how cromulent linking to NH is on B12's forums. The thing's standalone, as you note, and distributed as just the whole game already patched, and is possibly somewhat illegal, copyright wise. Poke about suggests that genesis might be going freeware in the near-ish future, but so far as I'm aware it's still commercial and other than something possibly unintentional from the main site (apparently you can download a demo and then patch it with an official patch and that'll remove the copyright protection), there's not been official indication the thing's welcome to be flapping free in the wild.
... that said, yeah, it adds a fair amount to the already pretty nice (if perhaps a bit samey after a bit) Eador: G. Bit unstable, though, from what I remember. Not enough to notice immediately, but enough to make actually getting through the whole of some of the later (i.e. larger) maps an occasional crap shoot. Which is rough, considering it's not terribly likely to start being an issue until you're a fair bit into a map (which is to say, you just ran an hour or three of play into a bug wall). Still. Pretty sizable expansion/improvement if you like the original.