Okay, so this game might be satire, but I still really like it. Characters all have one stat: Perception. They also have Keywords that describe the kind of things they perceive and what they can do about those things. The examples are "danger," "magic stuff," and "shiny things."

There's no gm/dm, so players just take turns being the one who rolls the baseline die everyone else compares their perception checks to. They describe what the characters see based on their results and the keywords used, and then the players describe what they do about it. If you noticed a thing, you can act on it.

It's a super short, streamlined game that kind of makes fun of the classic dungeon crawl, but it's also just a fun, easy way to do a collab story that still has a mechanics baseline to it. If nothing else, it's free.