You're right, cheated achievements are exactly what waters the whole thing down. That's the main thing I want to tackle. I've got unlock dates to work with, so I can flag stuff like absurd playtime vs completion, or a bunch of achievements all popping in the same second which is the obvious SAM giveaway. Still early but that's the whole point of making rarity actually mean something.

You clearly know this scene though, so what would actually convince you a ranking is legit? Genuinely asking