Okay, I finally got around to actually playtesting my mission. It was pretty harrowing until reinforcement, just as I hoped.
The teams in the lower buildings fought off zombies quite handily, mostly because I wrote the scenario so I knew where they'd come from. A couple worrying moments when guys were wounded or the mortar team had to reload, but I didn't lose anybody.
Then the bikes showed up.
A lot of really crap shooting doomed the north building. The officer was the first casualty, cut down after two turns dueling with bikers who came through the walls. Flame wagons got most of the others. After just a couple turns, the only guy left was a Panzerklein. Not the one that started up there either, the one from the southeast - he'd been wounded on the third turn, and still marched all the around the catwalk up to the other corner. He held up the whole invasion for four turns before he died after shooting his last round.
Meanwhile, the gunner and soldat teams in the southwest had nearly twenty kills each holding their corner unscathed, despite a biker that crashed through the window and survived being shot in the face for two turns. Of course nobody would have survived without the Panzerarbeiter. When the reinforcements arrived, I rolled them up just fine. Then the program crashed on turn 26.
Some tips for people new to the program who are having trouble:
Units can charge (based on their endurance), which lets them move farther, but some weapons can't be fired then.
Units which don't move can be put on Overwatch in the targeting phase. Unlike X-COM, there's no Reaction system - if an Overwatch unit sees an enemy, they shoot at it.
Units can pick up ammo - that's the trash laying around on the floor. Right-click the terrain to see what it is. Picking stuff up take a lot of movement points. The mortar fires grenades, and all bullets are the same. The one problem with this is the MG-42 - if the unit's Mauser isn't full, it'll reload that first.
Things I've learned:
Panzershreks were completely useless - I didn't see them do damage to anything even once. I don't know what's wrong with them, but I'll test it.
MG-42s are similarly useless, they're damaging enough, but need to fire more.
The officer is also useless, as an officer anyway. The game gives a morale bonus to every unit that sees an enemy die, and they stack and don't go away. By the third turn, every soldier has maxed morale, and never comes down again. There's no way to edit this, the program just isn't built for horde battles.
The Panzerarbieter is actually bugged - it's mortar has 50 rounds, because it shares a stance with the Panzerklein. It needs it's own mobile weapon anyway, so I'll deal with that next.
Still putting together ideas for more units, people, etc. Obviously, exploring the engine first so you what's possible is recommended. I was thinking BEES could work as a weapon - I'd replace the Etheral graphics, so it would be like a flamethrower of BEES.