After chatting with the dozen or so of my fellow GMs crazy enough to trot something out in front of strangers (and deep in the woods, no less – what the heck were we even thinking), we came up with some sound advice for anyone prepping a one-shot for a convention, great or small.
1. Live by the KISS rule
“Keep it simple, stupid” is a principle in system design that lives at the core of a good one-shot. The more complex and fancy you get, the less wiggle room you leave yourself. And you will need wiggle room. You will need it by the truckload.
As a good rule of thumb, once you’ve finished writing out the plot you expect to have happen, carve out two or three scenes and toss ’em aside. Keep them on hand as optional segments you can tune in on the fly, but don’t count on needing them. It’ll leave you space to maneuver if things fall behind schedule.
In general, if you take the time to plan out how long you think your one-shot is going to take, multiply that by three. That’s how long it’ll actually take once the players get involved. Since you’re probably working inside a semi-rigid, typically 4-hour block, it’s much better to err on the thin side and count on the players to pad things out on their own.
The simpler, the nimbler, the better.
2. Reward your players early and often
In a longer campaign, many GMs space out rewards to once every few sessions and juggle them between XP/advancement and money/rewards. The same pattern follows in a one-shot, but the effort-to-bonus ratio shifts toward the latter, and the types of rewards change.
A one-shot is typically the definition of ‘you can’t take it with you,’ so give your players rewards they can use right then and there. Action Points are popular; if your system doesn’t have them, add some in anyway. Make them physical: tokens, cards, poker chips – something tactile that they can cash in and keep track of, and that you can quickly see from across the table.
Items also make good rewards, but skip the +stat bonuses and “keen” weapons. Interesting and unique beats bigger and better in any one-shot. Go weird.
A talking dagger that loudly shouts the organ it just pierced when your perform a successful backstab. An impressive cyberdeck previously owned by a famous internet porn star, with an avatar you can’t change. A horn that summons a swarm of rabid woodland creatures to attack your enemies. Useful – but still weird. That adds up to memorable.
Con games are also one of the rare times an item like this is all fun and no terrible plot-ending oversight, so it’s the perfect time to unleash the strange so you all can enjoy what the nose hair of Vecna really looks like in play.
3. Give your players fumble safety nets
The worst and quickest way to bring an end to the fun of a one-shot is, sadly, largely out of your control: bad dice. Everybody rolls a 1 sometime (or a 99, depending on your system). Failure happens, and while it’s necessary, most of the countermeasures to death in any given system are designed for campaigns, not one-shots.
So when it’s that climactic scene, or what should be an easy hop over a tiny pit trap, a critical fumble at the wrong time can suck all the joy right out of a game if you don’t have a plan ready to counter it.
If you’re dealing in Action Points already, you might already have safety nets built-in that your players themselves can cash in to fish themselves out of a jam (reroll a roll, add +2, convert a crit fumble to a regular failure, etc).
I recommend also creating rules to let players fish each other out when one of them is dry on AP (or only one player is rolling poorly that day). Let other players spend their Action Points to save a friend. It has the added bonus of making the success (or the avoidance of terrible failure) a team effort, which is a great dynamic in a con game where most of your players don’t know each other going in.
Worst case, have some backup plans for ways to turn terrible game-ending fumbles into comically embarrassing fumbles instead. Observe:
“You run up to the pit trap, but don’t even reach it, tripping on a rock on the way and falling on your face, skidding up to the lip until you’re staring out at the row of bloody spears below. You are dazed for 1 round, and can try again once your head (and your dignity) recover…”
4. Keep things moving always
Remember what I said about time? You don’t have as much as you think, and nothing eats it up like waiting for 6-8 people to make up their minds about what to do next. Don’t be shy about coaxing your players when they seem genuinely lost. Prompt them, in-character if you’re able, out-of-character if you have to, but don’t let them flounder.
Momentum is your best friend in a one-shot. Velocity covers all manner of flaws in the design but letting folks get swept up in the energy of making progress.
Mind you, if your players are milking a scene together, there’s no need to stamp all over the fun. Your best chance to tighten up the flow is whenever there’s a decision the party needs to make. Paint that clear path forward, though remember: even in a one-shot, players can be resistant to railroading (though often less so than in a campaign).
That’s when you have the building shake under their feet. Put a very real (and in-character) countdown clock on their decision-making process. Short circuit the overplanning and emphasize the KISS principle to your players to get them up and moving so that they don’t spend half the night idling around the table asking “Gentlemen, how exactly do we kill Superman?”
Naturally, all that assumes that you respect the clarity ratio and have left enough clues for them to know what to do next. If they idle at any point for more than 10-15 minutes, it may be time to set up a neon sign pointing them to the next step.
5. Start tight, get loose
In the chaotic whirlwind that is your one-shot, rules are your friend at first. They’ll guide things like those little bumpers at the bowling lane until people figure out the basics and get their bearings. For many of them, it’ll be the first time seeing this ruleset, or your flavor of house rules. Either way, keep it taut at the start. But only at the start.
Once things get moving, let the rules get a little lax to make way for what are bound to be some crazier, chancier plans on the part of your players than you might see in a campaign (or than the rule makers accounted for). Let your players go nuts, even if it doesn’t exactly fit what’s on the sheet or in the table on page 187.
Keep in mind, you’re giving leeway, not tossing the book in the trash. Leave some structure. But if your player needs five more feet to connect on a brilliant throw, now’s the time to fudge the numbers to help make it a hit.
For the final fight, get ready to toss it all to make way for the majestic madness your players concoct. The system they’ve been playing within the boundaries of for the past few hours will keep them reined in on its own for the most part. When they decide to huck the unstable nuclear core into the reactor bed by ricocheting it off the bad guy’s noggin to halt the fatal meltdown, the rules aren’t paramount anymore. No one’s going to care much what the book says when your version involves the three-point bank shot that saved the world.
And that’s the kind of con game everyone remembers.