When we were still young in the ways of Lady Blackbird, a good friend of mine decided to use its remarkable and flexible system to run a genre dear to his heart: cyberpunk. He crafted characters with interlocking keys and traits to form a lean, mean heist team, came up with a starting scenario, and we gleeful players set forth to take the world by storm. I played Zero Cool, resident netrunner and annoying kid criminal extraordinaire. We played this game for a few sessions and definitely had some good times, but the game eventually trailed off, and we haven't come back to it since.
The game didn't work for a few reasons - one of which was that we were trying to play with more people than usual, always a tricky adjustment - but the one I want to discuss today is about system and genre. Cyberpunk stories are about a grossly unfair world, in which the haves dictate to the have-nots by dint of technology, capital and brute force, and criminality is the last best hope of freedom. It's about a society, in short, which says No at every turn. In contrast, Lady Blackbird is a system which jubilantly cries Yes! Yes!
A simple example from play: one of our characters was an artificial being equipped with an unspecified number of gadgets and attachments. At one point, we had caused a stampede in a crowded dance club. Most of us flowed with the crowd; the artificial being had drawn a lot of attention and needed a quicker exit, so his player triumphantly declared that he fired his onboard rockets and escaped up into the air. The players laughed at the audacity of the world-building and cheered at the sheer style of the exit; our GM, though, hesitated. The advice Lady Blackbird gives for GMs is to say yes or roll the dice. Personal rockets just weren't part of his conception of the universe, though. Cyberpunk can fall anywhere on a broad spectrum, and his concept was of a gritty universe without any of the trappings of far-flung SF. The player had found something that he couldn't say Yes to; it was an awkward moment of conflict that took several minutes for us to resolve and put a damper on the whole session.
LB wasn't the right system for the story we were trying to tell. The story was too much about the characters being told No, and finding a way around it, but the whole time the rules were telling us Yes, telling us we could try this or that and it would work - and when that spirit collided with the fiction, it wasn't a pretty picture.
Today some members of my group were discussing the idea of "vanity projects" for each of us, games that would let each play the perfect character for us. It started as a joke but it quickly produced some interesting ideas (I now eagerly await a noir game in which I'll get to play the femme fatale). One of the things that got the ball rolling was one player wishing she could play a pony, and it occurred to me that LB might be perfect for a Friendship Is Magic roleplay. You have keys to model the virtues, faults and relationships so essential to the show (yes I've watched it), and secrets for the ponies' magic abilities. Most of all, the tags and traits system is perfect for telling the players Yes just as the show says Yes to its characters. Yes, you can kick clouds out of the way! Yes, you know a spell to find gemstones! Yes, you can scold that dragon into behaving! The one problem I'm having is building in the one big No you'd need - a way to stop violence from ever coming up as a solution. The ponies do sometimes resort to violence, but in the world of the show it never solves things in a lasting way.
Conversely, I've seen attempts to model ponies in terms of say, Dungeons and Dragons. That seems like a project that's doomed to failure, because even if you model all of the things happen in the show and convince the players that their objective is not to kill goblins to get treasure, the system is still telling them No at every point - No, your Kick Clouds extraordinary ability doesn't let you ride on lightning, No, you don't have a "Travel to the moon" spell in your spellbook, No, your Diplomacy roll was too low to make friends with the roc.
So No systems - Dungeons and Dragons, say, or (one that's been on my mind lately) Fudge, aren't great for every story - but they're perfect for a project like my friend's cyberpunk game. If we'd been playing Fudge, he'd have been able to say, "Where's the rocket on your character sheet?" and that would have been the end of it, and everyone would have been happy. He'd have been secure knowing that he could create the universe he'd envisioned, and we would have gone back to our heist-planning and chaos-creation driven in the knowledge that we were bringing down the kind of society that prevented robots from having personal rockets.