Collectibles — Sets, Completion & Optional Pull

What it is. Optional goals with pull. Things to find, fill, and complete — a bestiary, a museum, a costume rack, a map’s every corner. Collectibles give self-directed players a reason to keep going after the critical path ends, without making that content mandatory.

Player fantasy / why it’s fun. “Just one more, and the set’s complete.” The almost-full grid is a magnet; the empty slot is an itch. The pull is closure — the collector’s satisfaction of a thing made whole.

When to use / when NOT

Use it when	Skip it when
You want optional long-tail goals for completionists	It would pad a tight, focused game with busywork
Exploration/thoroughness deserves a reward channel	The reward is required progress (then it’s not optional)
Cosmetics give a low-power, high-pull earn	Everything must matter mechanically

The discipline: collectibles are optional. The moment a set gates required power or the ending, it stops being a pull and becomes a tax. Keep the rewards expressive (cosmetics, lore, bragging rights) or modest (small bonuses) — never the only path to core power.

Variants

Variant	The pull is	Reward	Example
Sets to complete	Closure of a grid	Completion bonus / status	Bestiary, card album, museum
Cosmetics	Expression, status	Looks, zero power	Skins, dyes, titles
Map completion	Thoroughness	Reveal, %, secret	”100% map” ; hidden rooms
Cumulative unlocks	Milestone counting	New content at N	”Kill 100 → unlock weapon” (`system-meta-progression`)
Lore/knowledge	Curiosity	Story, world depth	Codex entries; audio logs (`world-narrative-delivery`)
Living dex / catch-em-all	The complete roster	Prestige, function	Pokédex; VS character unlocks

Tuning levers

Lever	What it controls	Healthy range / rule
Set size	Effort to complete	Big enough to be a journey, small enough to finish. Subdivide huge sets
Progress visibility	The itch	Show the empty slots — the grid with gaps IS the pull
Acquisition clarity	Fair vs guessy	The player should know how to get a missing one (or where to look)
Reward weight	Power vs cosmetic	Keep low-power / expressive; optional means optional
Completion payoff	The reason to finish	Give the 100% a real moment — a costume, a title, a secret
Missable density	Anxiety	Minimise permanently-missable items, or players stress-play

How it wires to Hayao

Collection is state; the grid is chrome. Owned/seen flags live in world.state (or the meta slice via SaveManager for cross-run dexes); the collection screen is showScreen() DOM, cosmetic where it renders in-world (CLAUDE.md invariant 4, [[FUN.md law 6]]).
Prove completability. Assert every collectible is reachable/obtainable — no item stranded behind a cut path or an impossible drop. This is the same connectivity sweep the roguelike runs on loot ([[FUN.md §10]]), and it catches the cruelest bug: a 99%-completable set.
Show the player-critical number. “3 of 12 found”, “2 nights left to catch it” — surface it, the way farming surfaces nights-in-season ([[FUN.md §15]]). Knowledge the completionist needs, made visible.
Persist across runs with SaveManager + SAVE_FORMAT_VERSION for meta dexes; the collection round-trips and hashes.

Fails when…

99% completable. One item unreachable (a cut spawn, a bugged drop) poisons the whole set. The reachability sweep is non-negotiable.
Mandatory sets. A collectible gating the ending or core power isn’t optional — it’s a chore with extra steps.
Invisible progress. No visible grid, no “N of M” — the pull evaporates.
Missable minefield. Many permanently-missable items → anxious, guide-dependent play. Minimise or make everything re-obtainable.
Hollow 100%. Completing the set gives nothing — the payoff must land.

Verify

Every collectible reachable/obtainable — connectivity sweep across seeds: [[FUN.md §10]].
Surface the completion number (found/total, time-left): [[FUN.md §15]].
Collection state persists & hashes (save round-trip): [[FUN.md law 7]].
The main game clears without completing any set (optional-means-optional): [[FUN.md law 4]].

Composes with

system-reward-schedules — variable-ratio drops feed set completion.
system-meta-progression — cross-run dexes and cosmetic unlocks.
system-economy — cosmetics as a currency sink with no power creep.
system-mastery-curve — hard-to-get collectibles reward skill, not just time.
world-narrative-delivery — lore collectibles deliver story with little text.