Well...since you asked.
We played my alternate Gormamorka game, Morkheim, which you can read about here.
https://www.dakkadakka.com/dakkaforum/posts/list/803560.page
Base rules are from Gorkamorka with a few modifications.
For "Da Zombie Siege" scenario it was 15 models on each side. Zombies started out six inches from the fence and orks automatically get the first turn. (We didn't use the rule where gunfire attracts additional zombies since this was already a big horde fight). No rout tests for the orks, it was a straight up fight to the death.
We treated the fence as a giant gate from Gorkamorka, so the zombies first order of business was to try and knock it down.
As for the game itself, the orks only lost 4 boyz, and the entire zombie horde was eliminated. Mostly due to some insanely good luck. (Took the zombies two turns to knock the fence down which was huge).
Many fun moments, glorious stikbombz, raining down from the ramparts, a skorcha lighting half the zombies on fire, and one brave ork that took on three zombies at once in hand to hand, and somehow held them off before reinforcements from inside the fort arrived.
All in all it felt like a finale episode from the Walking Dead with a good measure of orky goodness thrown in there. Rick Grimes would have been proud.