Liminalia progression loop research

liminalia

Research on implementing the core progression loop.

existing systems that form the loop

Every piece is already in the codebase — what's missing is the connection between them into a single cycle:

System	What it produces	Progression role
AgingService	Birthdays, retirements, deaths	Population turnover
EducationService	Educated citizens (level 1-3)	Skilled workforce pipeline
LabourService	Employed citizens at businesses	Economic production
BusinessService	Revenue, daily operations	Economic growth
CrimeService	Crime pressure from distress	Challenge escalation
HealthService	Illness from hunger/exhaustion	Challenge escalation
FireService	Random building fires	Challenge escalation
Economy	Treasury, UBI, taxes	City resources

proposed progression loop

founding (5 households, 48 citizens)
    ↓
simulate (citizens age, work, study, spend)
    ↓
economic growth (revenue → tax → treasury)
    ↓
challenge emergence (crime, illness, fire scale with population)
    ↓
player response (build police, hospital, fire station, school)
    ↓
maturation (population 30+, skilled workforce, stable)
    ↓
flourishing (complex economy, high tax base, sophisticated challenges)
    ↓
(cycle continues, difficulty scales with population)

citizen lifecycle

The loop is driven by citizen lifecycles:

1. Child (0-6): depends on household, no productivity
2. Student (7-18): attends school, gains education, no income
3. Worker (18-65): employed, earns wages, spends, pays taxes
4. Retiree (65+): depends on household, no labour market value
5. Death (age 90 or illness): estate settled, household vacancy

Education gates job quality: Engineers/Doctors/Teachers require secondary+ education. This creates a feedback loop: school investment → educated workers → better jobs → more tax revenue → more school investment.

challenge scaling

Crime pressure, illness rate, and fire risk all scale with:

• Population density (more citizens = more problems)
• Economic distress (poverty, debt, unemployment)
• Lack of civic infrastructure (no police = crime thrives)

This creates the player's core engagement: build the right institutions before problems overwhelm the city.

implementation direction

1. Population counter: track total citizens (world.Citizens.Count).
2. Difficulty multiplier in CrimeService, HealthService, FireService, tied to population milestones:
   • 0-30: founding (1x)
   • 31-60: growth (1.5x)
   • 61-100: maturation (2x)
   • 100+: flourishing (3x)
3. Multiplier applies to:
   • Crime pressure rate (CrimeService.AccumulatePressure)
   • Illness onset rate (HealthService.Accumulate)
   • Fire ignition chance (FireService.StartFires)
4. Treasury as progress metric: treasury balance shows city health. Below 0 = city deficit (emergency).
5. Day cycle: each simulated day = one full service tick. Player reviews city state daily and issues commands.

data model for progression

Add to SimulationWorld:

public int Population => Citizens.Count;
public double CityDifficulty => Population switch
{
    <= 30 => 1.0,
    <= 60 => 1.5,
    <= 100 => 2.0,
    _ => 3.0
};

The difficulty multiplier applies to:

• Crime pressure rate (CrimeService.AccumulatePressure)
• Illness onset rate (HealthService)
• Fire ignition rate (FireService)

This creates a natural difficulty curve: the bigger the city, the harder it is to maintain.

vertical slice test

A single test that validates the full progression cycle:

1. Seed world with 48 citizens and treasury
2. Fast-forward 30 simulated days
3. Assert: citizens aged (some birthdays), educated (school-age attended), employed (labour hired)
4. Assert: crime occurred (pressure crossed threshold), some resolved (police response)
5. Assert: treasury changed (taxes collected, UBI paid, business revenue)
6. Assert: population adjusted (deaths from aging/illness, retirements)

what to build first

1. Population milestone display (trivial — count citizens)
2. Difficulty multiplier in CrimeService, HealthService, FireService
3. Progression milestone events (founding → growth → maturation → flourishing)
4. Vertical slice test

what NOT to build yet

• Tech tree / era progression (out of scope — the citizen-driven progression IS the progression)
• City rating / score (treasury + population are sufficient metrics)
• Migration / immigration (citizens only enter via birth, leave via death/retirement)