Anyway, I think I have the main concept down, so really it's just fine-tuning the mechanics and difficulty level to have the appropriate push-pull that I want

For those that are curious, it's like...have you ever played Shadows over Camelot? Remember the Grail Quest portion, where you had to lay down Grail Cards faster than the game could counter them with Despair cards? Or heck, like Pandemic where you had to clear Pandemic tokens faster than the game could place them?

It's sort of between those two. A cooperative game with a tug-of-war base mechanic

and because it's me, it's a "fae magic leaking into Suburbia" theme, where the opposed forces are Wonder and Dread