Thank you so much Sodatree! I'm really glad you enjoyed it, and I absolutely love the Boxtrolls with more body horror comparison—that's such a fun way to describe the vibe I was going for.
Now, about your questions!
Masks: You don't start with all three available. You begin the game wearing The Mourner, while The Artisan and The Scholar are only gained after each Molt. Each Mask can only be used once, so over the course of the game you'll eventually cycle through all three before running out of identities.
Winning: The only actual victory condition is reaching 20 Humanity. Safehouses, Documentation, and Kinsfolk aren't things you have to collect—they're different objectives you can pursue each day, and each one pairs with a specific Mask for a +1 bonus to the roll. They're more about representing different ways your character integrates into human society rather than being required checkboxes.
Thanks again for playing and for taking the time to leave such thoughtful feedback. Your questions also showed me a couple of places where I can make the rules clearer in a future update!