Watching the demi-humans fight the zombies, I pace back and forth, observing their efforts as well as the zombies' habits. Compared to the skeletons, not all zombies didn't explode into purple smoke after getting attacked in the head. Some would flop down to the ground, trampled over by the zombies behind it while others would have to be stabbed over and over again before dying. However, everyone at the front was doing their best to keep the zombies at bay, and with the timely attacks from the archers in the back, there were no problems at the moment.
Every so often there would be a push against one side of the wall, with multiple zombies piling on one another in an attempt to breakthrough. Cleaves were used by the demi-humans to retaliate against the zombies and while the skill doesn't kill off all of them, it was able to stall enough time for someone else to come and help.