Ruin Explorer
Legend
Interesting - "trivial" is not really my experience!For my part, the ability to run a quick pickup game -- or any minimal to no prep game -- is familiarity with the system. If you know the system well, no matter what the system is, it is pretty trivial to put together interesting and "balanced" encounters on the fly. The rest is just whim, random charts or leaning on tried and true tropes.
Or rather perhaps there's a threshold of complexity beyond which I don't find that to be the case (FOR ME! I'm not saying it isn't for others).
Or more specifically, for it to work, you need a lot of pre-prepared material, particularly in the form of a lot of useful stat blocks. D&D has this via the MMs of course. But some games just don't have it. Most editions of Shadowrun don't have that, for example, or at least, if they do, I've never seen them (stat blocks tend to be fewer and more specific, or just are boring to work with). Other games require a level of familiarity with the specific stat blocks for them to work - to use another FASA example, Earthdawn. Maybe SWADE does have those? Cyberpunk 2020 kind of did, across various sourcebooks. Cyberpunk games in general whilst very trope-y you need to tread carefully if you're doing anything involving corporate environment because it's easy to improv your way into forgetting basic security elements (so if improvising cyberpunk genre stuff I tend to go for the "grimier" and more "street" oriented missions rather than corporate break-ins or the like).
The less I have to focus on pulling together mechanical stuff on the fly, the easier it generally is for me to DM no-prep, because I can focus more on the DMing - that's part of why I've found PtbA-type games to be very good for this kind of thing.