Thanks for the replies and the encouragement! I've kept thinking about this game, especially after watching Stranger Things which, like, yeah, that's what this is.

Actual work on the game has been almost non-existent as I've been busy with other projects but this has been percolating in the back of my head as something I want to get back to, but I think I need more experience with PbtA games before I can finish it. Fortunately I've been able to play a little Monsterhearts, and I'm in a PbP Masks game that is just starting up and if things turn out right I'll get to run Masks face-to-face as well. Fingers crossed.

In short, your input is appreciated and very useful. Thanks again!

So I thought I should put down my ideas for this. It's all very preliminary, first-draft kind of stuff.

Premise
Stephen King's It: the RPG, pretty much. The PCs are 10-12-year-old kids in a smallish town where children are being taken by a supernatural Other and the adults can't handle it.

Central themes are trust, friendship, and dealing with shitty situations when you're not equipped to do so.

Stats
When I sketch AW-hacks trying to find the right stats is always near the top of my list since the stats say so much about what the game is about. With KiT I'm not quite there yet, but these are my ideas so far:

• Trouble - Doing forbidden things, standing up to bullies, running away
• Mean - Hurting someone physically or emotionally, finding someone's weakness, bullying kids
• Creepy - Spying on someone, figuring out what someone wants
• Polite - Getting along with adults, probably school stuff as well
• Sweet - Lying to adults, comforting kids
• Imagination - Understanding the Other, coming up with plans

I used to think "Popular" or "Friendly" should be stats but right now I think the functions they had work better in playbooks or moves.

Speaking of which...

Playbooks
Like the stats, these are just basic ideas that will grow and change.

• The Popular Kid (Imagination? - maybe Popular needs to be a stat after all) - Good at getting other kids to go along with their ideas, leadership types, may be manipulative or self-sacrificing
• The Bully (Mean and/or Sweet) - Physically or socially gifted (maybe split those off into two different playbooks)
• The Trouble Kid (Trouble) - Noisy pranksters and tomboys, impopular with adults, brave but careless
• The Geek (Polite) - Well-behaved, good at finding information
• The Younger Sibling (Sweet) - Naïve, imaginative, good at hiding
• The Weird Kid (Creepy) - Socially awkward but also less bound by convention, willing to do what it takes

Basic Moves
Again, current rough ideas.

• Do something forbidden (Trouble) - Includes going to dangerous places, stealing etc
• Ask an adult for permission (Polite) - Can be used deceitfully but the request should be true in a literal sense
• Lie to an adult (Sweet)
• Stand up to a bully or older kid (Trouble) - Older kids are teenagers and they are dangerous
• Spy on someone (Creepy)
• Find someone's weakness (Mean)
• Figure out what someone wants or how they'll react (Creepy) - This is creepy because it requires thinking like an adult, and people find it creepy when kids do that
• Hurt someone (Mean) - Physically (anyone) or emotionally (kids only), maybe provoke older kids?
• Run away (Trouble) - The default way to handle anything scary
• Hide (Sweet? Creepy?) - Maybe a playbook move instead?
• Accept the horror (Imagination)

Dealing With Shit
On top of fighting a supernatural horror, the kids also have to deal with being kids. Every PC will have (at least?) one thing they're dealing with that is a source of shame and pain or insecurity, often tied to their family situation - distant parents, abusive parents, body image etc.

The key here is that the kids can't deal with their issues alone, but getting help from their friends means they have to make themselves vulnerable. This needs mechanical support of some kind that I haven't figured out yet - perhaps the equivalent of the AW sex moves? "When you tell someone about your pain..." Or! "When someone tells you about their pain, roll Hx, on a hit you help them, on a miss you push them away". There needs to be risk involved in this.

Speaking of Hx, I think I'll call that Trust or Friendship or something. Maybe.

Kids who haven't dealt with their pain are more vulnerable to the Other.

Miscellaneous
Kids will also have a number of fears that the Other uses to get to them.

If there's a damage track it will track emotional damage rather than wounds. Physical injuries will be handled in some other way - this isn't about trading harm with the Other but about confronting your fears and traumas.

If there's anything like barter it's probably more like favors, or maybe that's popularity? Hm.

That's about it. Feels good to have it all down in one place.

So for the last couple of days I've been thinking about making a game about kids going up against some supernatural threat the adults can't deal with because they don't believe in it while also dealing with their own shit of being kids. Very It. And yes, I know there are other games like this, but I want to make my own because I like making games.

My initial impulse was that using AW style moves and playbooks would work great for this. However, it seems that the way I envision this game it will have a strongly defined story arc, and specifically it will push towards an ending where the kids win or, well, they don't and that means they probably die or something. So the structure could be quite different from AW where things are more - I want to say "fluid", but I'm not sure that's the right word. Maybe it would be like playing AW where there's a single front? I dunno. My experience with AW is also fairly limited, having run a couple of sessions as well as three or four sessions of Monster of the Week but that's a different beast, and now that I think of it that's probably closer to what I'm doing anyway.

So did I just answer my own question that I have yet to pose, which is this: Does having a clear ending point with the game driving hard towards that mean I should use a different system, or does it just mean that while I can use the "superficial" mechanics of AW I should look hard at the procedures and make sure they support the rest of the game?

Or something else. Any advice gladly accepted.