Halloween Homebrew Game: Shotguns & Zombies

[Leewei]

Halloween is a couple of months off, and I've got a yen to run a one-shot game with some friends of mine.

The theme, as the title says, is a zombie apocalypse. I'm making a list of requirements and ideas for starters.
The game will ideally run about six hours.
The game will use online tools such as Discord and Zoom.
PCs will be trapped in an Ikea store for the entire run. The goal is to escape.
To escape, the PCs will need to accomplish a variety of goals, including creating a fortress of customized self-assembled furniture to hold off a horde of zombies, acquiring large amounts of meatballs, finding a store map, and rescuing other trapped shoppers.
PCs will have a number of abilities. Concepts include the runner-up regional MMA champion, a retired contractor, an exchange student (fluent in Swedish), and a few others.


My questions for you, dear reader, are:
Which game system is best for this sort of thing?
How can I make this the most fun for players?
What other challenges could I throw at the players?

[Breccia]

Which game system is best for this sort of thing?

GURPS. Just get a list of gun stats and the called shot hit location penalties for headshots and kneecapping. Be warned: GURPS takes a moderately realistic view of head shots, which is "you probably won't do it". You could probably relax them, or relax them with specific weapons (like a shotgun) to make those weapons more valued.

The biggest challenge I forsee is nobody will want to play the guy who does nothing but build the barricades, despite the obvious tactical advantage of zombies breaking in one by one instead of every window at the same time. While the contractor should get some kind of bonus if either making the barricade or supervising, he should also be able to MacGuyver traps of various brutality and/or hilarity.

Also, having shopped in my share of Ikea's, "Speaks Swedish" doesn't actually feel like a bonus. One, everything has instructions in English. Two, there will be showroom models already assembled. Three, quite frankly, their pre-assembled state is often a box filled with solid wood -- arguably more useful in that form than an assembled bookcase or rocking moose. What might be more useful would be an employee who not only knows the layout of the store (including location of meatballs, fuse boxes, cameras) but also has keys.

You could have a bronze/silver/gold coop prize system, and have each character have a goal which adds to it (rather than players competing against each other, which could lead to throwing an exchange student off a shelf into some zombies). These should be objective tasks of course, and possible solo but easier with a group. Could include such things as "I dropped the keys of my pickup truck that could carry a bunch of people and supplies if I got them back" to "I dropped my phone with video evidence, the public must know" to "we're going to need the medical supplies in the locked trunk in the basement". Let the players decide which are more important and more feasable. Goals probably shouldn't be reactive, such as "break 3 zombie grapples on other character" or "kill at least three zombes that make it into the break room". Give them a target and (when they get the map) at least one way to achieve that target, and see what happens.

Want to make it more challenging? Have some goals require the party splits up. The cliche is "fuse box is in the basement" but other options include lowering something from one floor to another using the windows, or cameras watching the halls only visible from the security room.

Want to get sadistic? Send a private message to one player, preferably one who would enjoy doing this of course, that their character is actually the villain. Their public task should, upon closer scrutiny, appear to be high-risk low-reward ("What's so special about your laptop?") and have them push for this task hard. The player should also claim their character has weak combat skills (true or false) because their own secret goal is to increase their chance of survival, with their own public task being completed, which means pushing everyone else to the front lines. The group should also get a bonus if they figure out that character is actually the villain. The villain's goal should also include directly or indirectly killing anyone who learns their secret, but not otherwise to kill other characters. This one's optional and works less and less with fewer players.

Be advised that hiding from zombies in an Ikea sounds pretty easy. Besides obvious places like under the sofas and beds, there's likely a subceiling and of course they could just get to the roof and barricade the only door. You're going to need to find a way to discourage "camping", such as making the threshhold for Bronze Medal slightly higher than "every character survives but no other goals obtained". Rescuing trapped survivors might work for that, if you either go Dead Rising and have the group only find out about them at specific times, or if they arrive late, or (my favorite) if players failing to find them in time adds to the number of zombies. Basically, if the group just wants to go barricade themselves on the roof and wait it out with no food, weapons, or medicine, regardless of how reasonable that sounds in a non-game situation, it'll ruin all your hard work if the players just decide to take the most boring route and end the game in ten minutes.

To make a horror encounter fun, it probably shouldn't be something the characters can actually clear. The players should always feel like there's more danger yet to come, so try not to engineer a situation in which the characters can just kill all the zombies, then have coffee and relax until the chopper arrives. Have a contingency plan or two in case this happens -- consider having a bus filled with zombies crash into the building, human looters with weapons climbing in windows or coming in through the roof, or a chafing dish accident sending out a wave of zomies on fire. Use whichever you think the game needs -- if the characters are handily beaitng all your scripted events, up the difficulty, if not, shelve them.

And of course, since I guarantee at least one of your players has read the Zombie Survival Guide or some such, consider making a change to your zombies from the currently accepted norm of "created by virus, killed by headshots". Not only does this add a layer of the unkonwn to your horror experience -- and the best horror is based on the unknown -- but the players will feel satisfaction when they figure out the way these special zombies work and use it to their advantage. You can have fun with this part -- just write down all the "damage types" you can think of and pick two at random, and decide how the zombies are resistant to everything but those two. Or, replace "head" with "what I roll on the body part hit location table" and try to justify that. It'll be hard to find a reason why a zombie dies with its feet broken, but it's pretty easy to justify why a no-foot zombie stops being a threat, which is just as good. Otherwise it could be a spore infection in the lungs, alien parasites floating in stomach acid, or Evil Dead hands.

End of the day, think of it like, well, a zombie movie. What could the characters do, that the audience would want to watch? What would the zombies do, that would make the audience fear for the characters? And what's the big climax? I realize I'm probably giving you more questions than answers, but let's be honest, what you're asking for sounds more like "start with a bunch of options and whittle it down" than "start with a baseline and work up".

P.S. You need special training to use a forklift. Just sayin'