Here's the gist:
- Easy to Learn: No one wants a rule book coma! It would be great if it had some super consistency across the rules. 1/2 page cheat sheet would be ok.
- Story-Focused: Epic moments, player agency, and plot twists galore!
- Light on Rules: Dice are fun, spreadsheets are not!
- No Maps Needed: Theatre of the mind for vivid storytelling!
- GM Friendly: Easy prep for epic adventures!
Bonus Points:
- Genre Mashup: Fantasy, Sci-Fi, or a wild mix?
- Flexible Play: One-shots or sprawling campaigns!
As I often do when these kinds of threads come up, I’m going to recommend Spire: The City Must Fall.
It ticks pretty much every box you've listed. The core mechanics fit on one page, and are easy to explain and understand. The system allows for consequences of multiple types, so it’s not all just combat (though there can be plenty of that, if you like). This means things veer off in unexpected directions.
The setting takes many familiar fantasy elements, and presents them in a new way. So there’s a lot that’s familiar, but it becomes new. The main element is the relationship between drow and high elves. But there are also gnolls and humans and gutterkin (a kind of goblin/kobold catchall). There are certainly fantastic elements… deities and religions and magic and wizardry… but also more modern elements, too… guns and printing presses and elevators and the like.
Oh and a haunted train system that’s tapped into a tear in reality and runs through alternate dimensions and timelines.
The basic premise is that the PCs are drow revolutionaries in the mile high city of Spire. They once rules the city, but a couple hundred years ago, the high elves took over. Since then, they’ve subjugated the drow, forcing them to work a durance, and sending many if them off as conscripts to fight a war with the gnolls of Far Nujab.
The PCs are members of a clandestine organization whose goal is to subvert high elf rule however they can. Outright revolution is not likely, but small acts of insurrection, sabotage, and skullduggery are possible. This lends itself to either a short game or one shot that revolves around a single mission, or a more long form campaign of the same cell over time.
It’s an excellent game with a fantastic core book. Even better, there’s a quickstart you can download in PDF for free from the publisher’s (Rowan, Rook, and Decard) site. So you can check it out without cost, and decide if you like it enough to pick up the core book.
There are also three campaign frames that you can download for free from their site. These are “adventure module” type scenarios, though they’re more situations that can be exploited than they are adventures to play through. The game doesn’t really lend itself to high amounts of prep given the abilities that the PCs have to change things up.
Again, I think it hits all your criteria. It’s a fun game that allows for a lot of player creativity and proactivity. The setting is evocative and strange, but still relatable.