Loved it!
Not only worthy of Madness, but also of zombie films. All the small little references to various zombie movies already made with lines and the characters you presented (from what I saw, original Dawn of the Dead, Day of the Dead, remake of Dawn of the Dead, Resident Evil Apocalypse, and even L4D) fit in to make a wonderful tapestry.
While not as over the top in the action as most madness, it was bloody, brutal and violent enough to fit in perfectly, as well as the small bits that were very madness styled in the action.
I like the use of Hydralisks and Mutalisks to make the zombie sounds. Creepy and unique. Another unique bit of your work in the madness world in Female characters. Saw them in one other piece, but they weren't very obviously female (aside from long hair and voices).
I hope I don't have to wait until next year to see the conclusion (or perhaps more if it comes to that, I love this particular series), but if I do, I can wait patiently for another flash as good as this one.
Also, to satiate my curiosity, what's the third one gonna be called?