We figured out that had the Elves simply ignored combat altogether and just ran for the exit, the Undead probably couldn't have stopped them. The Elves started with more models than the Undead, and when the Undead came on the field they were dispersed. Since the Undead couldn't run, once they got behind the Elves, that's where they stayed.
Archery didn't have much effect, since the scenario required moving and there was a lot of intervening gravestones. A force of all Glade Guards and a Hero would probably be unbeatable in this scenario. The dice really didn’t fall Roy’s way in this test.
Although the Undead won, I think the scenario is balanced against them. I would change the scenario a couple ways: Undead models start the game on a 1-3 on 1d6 (instead of a 1 or 2), and Undead reinforcements only have to be 3" away from Mortal models when they rise. You could rule that dead Mortal figs will come back as Zombies on a 1 on 1d6, but that may be too powerful.