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gameplay-mechanics skill

/skills/gameplay-mechanics

This skill helps you implement and balance core gameplay mechanics, feedback loops, and progression to deliver engaging, responsive player experiences.

npx playbooks add skill pluginagentmarketplace/custom-plugin-game-developer --skill gameplay-mechanics

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SKILL.md
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---
name: gameplay-mechanics
version: "2.0.0"
description: |
  Core gameplay mechanics implementation, system interactions, feedback loops,
  and iterative balance refinement for engaging player experiences.
sasmp_version: "1.3.0"
bonded_agent: 01-game-designer
bond_type: PRIMARY_BOND

parameters:
  - name: mechanic_type
    type: string
    required: false
    validation:
      enum: [combat, movement, puzzle, progression, economy]
  - name: complexity
    type: string
    required: false
    validation:
      enum: [simple, moderate, complex]

retry_policy:
  enabled: true
  max_attempts: 3
  backoff: exponential

observability:
  log_events: [start, complete, error]
  metrics: [engagement_time, action_frequency, balance_score]
---

# Gameplay Mechanics Implementation

## Core Mechanics Framework

```
┌─────────────────────────────────────────────────────────────┐
│                    ACTION → EFFECT LOOP                      │
├─────────────────────────────────────────────────────────────┤
│  INPUT          PROCESS          OUTPUT          FEEDBACK   │
│  ┌─────┐       ┌─────────┐      ┌─────────┐    ┌─────────┐ │
│  │Press│──────→│Validate │─────→│Update   │───→│Visual   │ │
│  │Button│      │& Execute│      │State    │    │Audio    │ │
│  └─────┘       └─────────┘      └─────────┘    │Haptic   │ │
│                                                 └─────────┘ │
│                                                              │
│  TIMING REQUIREMENTS:                                        │
│  • Input → Response: < 100ms (feels responsive)             │
│  • Animation start: < 50ms (feels instant)                  │
│  • Audio feedback: < 20ms (in sync with action)             │
└─────────────────────────────────────────────────────────────┘
```

## Feedback Loop Design

```
FEEDBACK TIMING LAYERS:
┌─────────────────────────────────────────────────────────────┐
│  IMMEDIATE (0-100ms):                                        │
│  ├─ Button press sound                                      │
│  ├─ Animation start                                         │
│  ├─ Screen shake                                            │
│  └─ Controller vibration                                    │
│                                                              │
│  SHORT-TERM (100ms-1s):                                      │
│  ├─ Damage numbers appear                                   │
│  ├─ Health bar updates                                      │
│  ├─ Enemy reaction animation                                │
│  └─ Particle effects                                        │
│                                                              │
│  LONG-TERM (1s+):                                            │
│  ├─ XP/Score increase                                       │
│  ├─ Level up notification                                   │
│  ├─ Achievement unlock                                      │
│  └─ Story progression                                       │
└─────────────────────────────────────────────────────────────┘
```

## Combat Mechanics

```csharp
// ✅ Production-Ready: Combat State Machine
public class CombatStateMachine : MonoBehaviour
{
    public enum CombatState { Idle, Attacking, Blocking, Recovering, Staggered }

    [Header("Combat Parameters")]
    [SerializeField] private float attackDamage = 10f;
    [SerializeField] private float attackRange = 2f;
    [SerializeField] private float attackCooldown = 0.5f;
    [SerializeField] private float blockDamageReduction = 0.7f;
    [SerializeField] private float staggerDuration = 0.3f;

    private CombatState _currentState = CombatState.Idle;
    private float _stateTimer;

    public event Action<CombatState> OnStateChanged;
    public event Action<float> OnDamageDealt;
    public event Action<float> OnDamageTaken;

    public bool TryAttack()
    {
        if (_currentState != CombatState.Idle) return false;

        TransitionTo(CombatState.Attacking);
        StartCoroutine(AttackSequence());
        return true;
    }

    private IEnumerator AttackSequence()
    {
        // Wind-up phase
        yield return new WaitForSeconds(0.1f);

        // Active hit frame
        var hits = Physics.OverlapSphere(transform.position + transform.forward, attackRange);
        foreach (var hit in hits)
        {
            if (hit.TryGetComponent<IDamageable>(out var target))
            {
                target.TakeDamage(attackDamage);
                OnDamageDealt?.Invoke(attackDamage);
            }
        }

        // Recovery phase
        yield return new WaitForSeconds(attackCooldown);
        TransitionTo(CombatState.Idle);
    }

    public float TakeDamage(float damage)
    {
        float finalDamage = _currentState == CombatState.Blocking
            ? damage * (1f - blockDamageReduction)
            : damage;

        OnDamageTaken?.Invoke(finalDamage);

        if (finalDamage > 5f) // Stagger threshold
        {
            TransitionTo(CombatState.Staggered);
            StartCoroutine(RecoverFromStagger());
        }

        return finalDamage;
    }

    private void TransitionTo(CombatState newState)
    {
        _currentState = newState;
        _stateTimer = 0f;
        OnStateChanged?.Invoke(newState);
    }
}
```

## Resource Economy System

```
ECONOMY BALANCE FORMULA:
┌─────────────────────────────────────────────────────────────┐
│  INCOME vs EXPENDITURE:                                      │
│                                                              │
│  Hourly Income = (Enemies/hr × Gold/Enemy) + PassiveIncome  │
│  Hourly Spend  = (Upgrades + Consumables + Deaths)          │
│                                                              │
│  BALANCE RATIO:                                              │
│  • < 0.8: Too scarce (frustrating)                          │
│  • 0.8-1.2: Balanced (meaningful choices)                   │
│  • > 1.2: Too abundant (no tension)                         │
│                                                              │
│  EXAMPLE STAMINA SYSTEM:                                     │
│  ┌───────────────────────────────────────────────────────┐  │
│  │  Max: 100  │  Regen: 20/sec  │  On Hit: +10           │  │
│  ├───────────────────────────────────────────────────────┤  │
│  │  Light Attack: -10  │  Heavy Attack: -25              │  │
│  │  Dodge: -15         │  Block: -5/hit                  │  │
│  │  Sprint: -5/sec     │  Jump: -8                       │  │
│  └───────────────────────────────────────────────────────┘  │
└─────────────────────────────────────────────────────────────┘
```

## Progression Systems

```
PROGRESSION CURVE:
┌─────────────────────────────────────────────────────────────┐
│  Power                                                       │
│    ↑                                                         │
│    │                                    ╱───── Late Game     │
│    │                              ╱────╱       (slow, goals) │
│    │                        ╱────╱                           │
│    │                  ╱────╱                                 │
│    │            ╱────╱       Mid Game                        │
│    │      ╱────╱             (steady progress)               │
│    │ ╱───╱                                                   │
│    │╱ Early Game (fast, hook player)                        │
│    └────────────────────────────────────────────────→ Time   │
│                                                              │
│  XP CURVE FORMULA:                                           │
│  XP_needed(level) = base_xp × (level ^ growth_rate)         │
│  • growth_rate 1.5: Gentle curve (casual)                   │
│  • growth_rate 2.0: Standard curve (balanced)               │
│  • growth_rate 2.5: Steep curve (hardcore)                  │
└─────────────────────────────────────────────────────────────┘
```

```csharp
// ✅ Production-Ready: Progression Manager
public class ProgressionManager : MonoBehaviour
{
    [Header("Progression Config")]
    [SerializeField] private int baseXP = 100;
    [SerializeField] private float growthRate = 2.0f;
    [SerializeField] private int maxLevel = 50;

    private int _currentLevel = 1;
    private int _currentXP = 0;

    public event Action<int> OnLevelUp;
    public event Action<int, int> OnXPGained; // current, required

    public int XPForLevel(int level)
    {
        return Mathf.RoundToInt(baseXP * Mathf.Pow(level, growthRate));
    }

    public void AddXP(int amount)
    {
        _currentXP += amount;
        int required = XPForLevel(_currentLevel);

        OnXPGained?.Invoke(_currentXP, required);

        while (_currentXP >= required && _currentLevel < maxLevel)
        {
            _currentXP -= required;
            _currentLevel++;
            OnLevelUp?.Invoke(_currentLevel);
            required = XPForLevel(_currentLevel);
        }
    }

    public float GetProgressToNextLevel()
    {
        return (float)_currentXP / XPForLevel(_currentLevel);
    }
}
```

## Movement Mechanics

```
PLATFORMER FEEL PARAMETERS:
┌─────────────────────────────────────────────────────────────┐
│  MOVEMENT:                                                   │
│  • Walk Speed: 5-8 units/sec                                │
│  • Run Speed: 10-15 units/sec                               │
│  • Acceleration: 20-50 units/sec²                           │
│  • Deceleration: 30-60 units/sec² (snappier = higher)       │
│                                                              │
│  JUMP:                                                       │
│  • Jump Height: 2-4 units                                   │
│  • Jump Duration: 0.3-0.5 sec                               │
│  • Gravity: 20-40 units/sec²                                │
│  • Fall Multiplier: 1.5-2.5x (faster fall = tighter)       │
│                                                              │
│  FEEL ENHANCERS:                                             │
│  • Coyote Time: 0.1-0.15 sec (jump after leaving edge)      │
│  • Jump Buffer: 0.1-0.15 sec (early jump input)             │
│  • Variable Jump: Release = shorter jump                    │
│  • Air Control: 50-80% of ground control                    │
└─────────────────────────────────────────────────────────────┘
```

## Event-Driven Architecture

```
EVENT SYSTEM PATTERN:
┌─────────────────────────────────────────────────────────────┐
│  ACTION EXECUTED                                             │
│       │                                                      │
│       ▼                                                      │
│  ┌─────────────────────────────────────────────────────┐    │
│  │              EVENT DISPATCHER                        │    │
│  │  DamageDealt(amount, position, type)                │    │
│  └─────────────────────────────────────────────────────┘    │
│       │                                                      │
│       ├──→ VFX System: Spawn damage numbers                 │
│       ├──→ Audio System: Play hit sound                     │
│       ├──→ UI System: Update health bar                     │
│       ├──→ Camera System: Screen shake                      │
│       ├──→ AI System: Alert nearby enemies                  │
│       └──→ Analytics: Log combat event                      │
│                                                              │
│  BENEFITS:                                                   │
│  • Systems don't need direct references                     │
│  • Easy to add/remove observers                             │
│  • Same event triggers multiple effects                     │
│  • Easy networking (replicate events)                       │
└─────────────────────────────────────────────────────────────┘
```

## Balance Iteration

```
RAPID BALANCE WORKFLOW:
┌─────────────────────────────────────────────────────────────┐
│  1. PLAYTEST (15-30 min)                                     │
│     → Watch players, note friction points                   │
│                                                              │
│  2. ANALYZE (5-15 min)                                       │
│     → What felt wrong? Too easy/hard?                       │
│     → Check telemetry data                                  │
│                                                              │
│  3. ADJUST (5-10 min)                                        │
│     → Change ONE variable at a time                         │
│     → Document the change                                   │
│                                                              │
│  4. TEST (5 min)                                             │
│     → Verify change has intended effect                     │
│                                                              │
│  5. REPEAT                                                   │
│     → Target: 4-6 iterations per hour                       │
└─────────────────────────────────────────────────────────────┘

BALANCE SPREADSHEET FORMAT:
┌──────────┬────────┬─────────┬─────────┬──────────┐
│ Weapon   │ Damage │ Speed   │ Range   │ DPS      │
├──────────┼────────┼─────────┼─────────┼──────────┤
│ Sword    │ 10     │ 1.0/sec │ 2m      │ 10.0     │
│ Axe      │ 20     │ 0.5/sec │ 1.5m    │ 10.0     │
│ Dagger   │ 5      │ 2.0/sec │ 1m      │ 10.0     │
│ Spear    │ 12     │ 0.8/sec │ 3m      │ 9.6      │
└──────────┴────────┴─────────┴─────────┴──────────┘
```

## 🔧 Troubleshooting

```
┌─────────────────────────────────────────────────────────────┐
│ PROBLEM: Controls feel unresponsive                         │
├─────────────────────────────────────────────────────────────┤
│ SOLUTIONS:                                                   │
│ → Add immediate audio/visual feedback on input              │
│ → Reduce input-to-action delay (< 100ms)                    │
│ → Add input buffering for combo actions                     │
│ → Check for frame rate issues                               │
└─────────────────────────────────────────────────────────────┘

┌─────────────────────────────────────────────────────────────┐
│ PROBLEM: One strategy dominates all others                  │
├─────────────────────────────────────────────────────────────┤
│ SOLUTIONS:                                                   │
│ → Nerf dominant option OR buff alternatives                 │
│ → Add situational counters                                  │
│ → Create rock-paper-scissors relationships                  │
│ → Add resource costs to powerful options                    │
└─────────────────────────────────────────────────────────────┘

┌─────────────────────────────────────────────────────────────┐
│ PROBLEM: Players don't understand mechanic                  │
├─────────────────────────────────────────────────────────────┤
│ SOLUTIONS:                                                   │
│ → Add clearer visual/audio feedback                         │
│ → Create safe tutorial space                                │
│ → Use consistent visual language                            │
│ → Add UI hints or tooltips                                  │
└─────────────────────────────────────────────────────────────┘

┌─────────────────────────────────────────────────────────────┐
│ PROBLEM: Progression feels grindy                           │
├─────────────────────────────────────────────────────────────┤
│ SOLUTIONS:                                                   │
│ → Reduce XP requirements                                    │
│ → Add more XP sources                                       │
│ → Give meaningful rewards more frequently                   │
│ → Add catch-up mechanics for late content                   │
└─────────────────────────────────────────────────────────────┘
```

## Mechanic Comparison

| Mechanic | Skill Floor | Skill Ceiling | Feedback Speed |
|----------|-------------|---------------|----------------|
| Button Mash | Low | Low | Instant |
| Timing-Based | Medium | High | Instant |
| Resource Management | Medium | High | Delayed |
| Combo System | High | Very High | Instant |
| Strategic | Medium | Very High | Delayed |

---

**Use this skill**: When implementing core mechanics, balancing systems, or designing player feedback.

Overview

This skill implements core gameplay mechanics, system interactions, feedback loops, and iterative balance refinement to create engaging player experiences. It provides production-ready patterns for combat, movement, progression, resource economy, event-driven architecture, and rapid balance workflows. The focus is on measurable timing, feel, and maintainable systems suitable for engine-specific integration in Python-based tooling and pipelines.

How this skill works

The skill codifies action→effect loops and layered feedback timing to ensure input feels responsive and outcomes are clear. It offers state machines for combat, progression managers for XP and levels, parameterized movement profiles, and economy formulas to balance income vs. expenditure. An event-driven pattern decouples systems so VFX, audio, UI, AI, and analytics respond to the same game events without tight coupling.

When to use it

  • Designing or refactoring core combat and input systems to improve responsiveness
  • Defining movement and platformer feel parameters for character controllers
  • Creating progression and XP curves for early-to-late game pacing
  • Balancing in-game economies, stamina, and consumable systems
  • Implementing event-driven architecture for modular systems and networking

Best practices

  • Target sub-100ms input→response and sub-50ms animation start for perceived responsiveness
  • Layer feedback: immediate (sound/animation), short-term (numbers/particle), long-term (XP/achievements)
  • Change one variable at a time during balance iterations and document each tweak
  • Use event dispatchers so systems subscribe to events instead of holding direct references
  • Measure balance with simple ratios (income vs. expenditure) and tune toward 0.8–1.2

Example use cases

  • Implement a combat state machine with wind-up, active, and recovery phases and stagger logic
  • Tune jump, gravity, coyote time, and air control to achieve desired platformer feel
  • Build a progression manager computing XP requirements with configurable growth rates
  • Run rapid balance loops: playtest, analyze telemetry, adjust one parameter, retest
  • Design an economy model that calculates hourly income and flags scarcity or abundance

FAQ

How do I make controls feel more responsive?

Add immediate audio/visual feedback, reduce input-to-action latency below 100ms, implement input buffering, and check frame rate stability.

What's the simplest way to balance a dominant strategy?

Adjust one variable: nerf the dominant option or buff alternatives, add situational counters or resource costs, and re-test iterations quickly.