What it is. You author a system — a factory, a park, a colony, a household — then tune its inputs, throughput, and demand until it runs without you. The verbs are place, connect, price, staff, cut. Play is diagnosis and adjustment, not reflexes.

Player fantasy / why it’s fun. The dopamine is legibility earned: a mess of red numbers you slowly turn green, then watch tick over on its own. You are the invisible hand that finally understands its own machine.

Pillars (exactly 3)

1. Legible systems. Every number traces to a cause the player can see and touch. If a queue backs up, the bottleneck is findable. Opacity is the enemy — see pattern-readability.
2. Meaningful optimization. There is always a better configuration, and the delta is felt. Choices trade off, not dominate — dodge antipattern-boring-optimal where one build wins forever.
3. Escalating load. Demand, complexity, or scale ratchets up so a solved layout becomes tomorrow’s bottleneck. Pressure, not a plateau.

The loop stack

The loop is observe → hypothesize → adjust → watch it settle. Keep the settle-time short enough to close the feedback fast; see pattern-feedback-loops and pattern-mastery-and-flow.

Essential systems

• system-economy — the spine. Money or a proxy currency that flows in from output and out through upkeep; the ledger must balance to survive.
• system-resource-loops — raw → refined → sold, with buffers and spoilage. This is where bottlenecks live.
• pattern-feedback-loops — the demand curve. Success raises expectation, cost, or scrutiny so the target keeps moving.
• system-progression — an unlock spine (new buildings, tiers, districts) that gates complexity so system-onboarding can land one concept at a time.
• system-difficulty-and-dda — scenario pressure: quotas, deadlines, disasters that force replanning.
• system-inventory-and-ui — the interface is the game. Graphs, heatmaps, and overlays are your primary telegraph; a hidden number is a dead mechanic.

Content & difficulty model

• Scenario, not level. Ship hand-authored maps with a starting condition, a win/loss ledger, and a twist constraint (scarce water, hostile winter, a fixed footprint). Reference anchor-frostpunk‘s scenario framing.
• Difficulty is demand, not damage. Raise quotas, shrink margins, add a competing sink. The curve is economic tension — pace it per pattern-pacing-and-tension.
• Sandbox unlock late. A free-build mode is the reward for beating the authored pressure, not the default first experience.
• Determinism buys trust. A fixed-seed economy means a spike is diagnosable, not luck. Route every random event through a deterministic RNG; see system-procgen-design for how to seed varied-but-fair scenarios.

Signature-mechanic seeds

• Tycoon but you can never expand, only rebalance (constraint). The footprint is fixed at frame one — no new land, no new buildings. Every gain comes from reconfiguring what exists: repurpose, re-route, re-price. Optimization goes deep instead of wide, and the puzzle is legibly bounded.
• Management but the thing you run is a single family (perspective). Zoom the tycoon lens onto one household — budget, chores, moods, aging. Currencies are money and trust and time; a bad quarter isn’t bankruptcy, it’s a strained relationship. Human weight replaces the spreadsheet.
• The demand curve talks back (agency). Your customers/citizens are named agents with memory — see anchor-rimworld. Cut a corner and a specific person suffers, and remembers; optimization acquires a conscience.
• Optimize toward shutdown (goal-inversion). Victory is winding the machine down cleanly — a factory you must decommission, a fund you must spend to zero on the right things by a deadline. The tycoon loop, run in reverse.
• You inherit a broken machine (starting-state). Open on someone else’s mess — miswired, over-leveraged, badly zoned. The first session is pure archaeology: understand it before you touch it.

Common pitfalls

• Spreadsheet without stakes. Numbers move but nothing is at risk that the player cares about — the core trap. Attach human or moral weight: a person, a place, a promise. Without it you get antipattern-fake-choice dressed as depth.
• antipattern-boring-optimal — one layout dominates and every map collapses to it. Make trade-offs genuine and contexts differ.
• antipattern-currency-spaghetti — six currencies that all convert to money. Keep sinks and sources few and meaningful.
• antipattern-false-depth — knobs that look like choices but never change outcome. Cut them.
• antipattern-endless-tutorial — over-gated onboarding that explains the machine you’d rather discover. Teach one system, then step back.
• antipattern-solved-metagame — once players find the build order, escalation must outrun it or the game is over.

Anchors

• anchor-frostpunk — the moral-weight exemplar: every efficiency choice is also an ethical one; the primary reference for this genre.
• anchor-rimworld — named-agent management where the story emerges from the system; see also pattern-emergence.
• anchor-factorio — the throughput-optimization purest form; bottleneck-hunting as the whole game.
• anchor-mini-metro — legibility and constraint distilled: minimal inputs, a rising demand curve, no fat.
• anchor-stardew-valley — the cozy end, where management wears the skin of a genre-farming-sim.

Neighbors worth studying: genre-city-builder, genre-incremental (the demand curve without the map), genre-4x (management at civilizational scale).

Verify

Prove the loop against design/FUN.md#17-·-city-builder — is the bottleneck findable, does the demand curve keep the target moving, does a tuned system visibly run itself? Judge looks via process-refine-and-handoff.