Duality

https://nunnyu.itch.io/duality https://itch.io/jam/gamedevjs-2025/rate/3504627

25th out of 411 in Gamedev.js Jam 2025 (and 12th in audio!)

Overview

Duality is a 2D puzzle-platformer game built with Unity Engine, featuring dual-character cooperative gameplay mechanics. Players control two complementary characters—Lumine (light) and Umbra (dark)—navigating through interconnected levels that require strategic coordination to progress.

Technology Stack

• Game Engine: Unity 6000.0.32f1
• Programming Language: C#
• Rendering Pipeline: Universal Render Pipeline (URP) 17.0.3
• Input System: Unity Input System 1.11.2
• Physics: Unity Physics2D
• Audio: Unity Audio System
• Platform: 2D

Core Architecture

Game State Management

• Singleton Pattern: Implemented via ManageGame class for global state management
• Scene Management: Multi-level system with dynamic loading and progression
• Persistent Data: Game manager persists across scene transitions using DontDestroyOnLoad

Dual Character System

The game features two distinct playable characters with complementary mechanics:

• Lumine (Light):

  • Controlled via WASD keys
  • Health represented as brightness (decreases in darkness)
  • Attacks with light-based projectiles
  • Stronger at low health (inverse health-to-power scaling)

• Umbra (Dark):

  • Controlled via arrow keys
  • Health increases in bright zones (opposite mechanics)
  • Attacks with dark-based projectiles
  • Complementary power scaling system

Systems Architecture

Health & Lighting System

• Dynamic Health Model: Health directly influences lighting intensity in real-time
• Territory-Based Mechanics: Characters take damage in opposing territory zones
• Regenerative System: Health regeneration when in safe zones
• Visual Feedback: Lighting intensity scales with character health using Light2D component

Combat System

• Directional Attack System: Attacks dynamically orient based on movement input
• Dynamic Scaling: Attack size and damage scale inversely with health (risk-reward mechanic)
• Collision Detection: Circle collider-based hit detection with type-specific damage
• State-Dependent Visibility: Attacks only visible/active during movement

Level Progression

• Progressive Level System: 7 levels (Level0-Level6) with incremental difficulty
• Gate Mechanics: Key-based progression requiring both characters to collect keys
• Win Condition: Both characters must reach their respective exits (with the keys)
• Failure State: Reset on death of both characters or timeout

Audio Management

• Singleton Audio Manager: Centralized audio system with persistent instance
• Dynamic Audio Sources: Runtime audio source creation and management
• Sound Categories: Title music, gameplay themes, effect sounds (death, key collection, enemy destruction)
• Loop Management: Configurable looping for background music

Timer System

• Level Time Limits: Configurable per-level time constraints
• Visual Feedback: UI bar with color transitions indicating time remaining
• Warning System: Visual flashing when time runs low (5 seconds remaining)

Technical Highlights

Performance Optimizations

• Singleton pattern implementation prevents duplicate manager instances
• Efficient Update/FixedUpdate separation for physics calculations
• Vector2 operations for 2D-specific calculations
• Linear interpolation for smooth movement transitions

Code Quality

• Separation of concerns across specialized scripts
• Modular design allowing independent system updates
• Serialized fields for designer-friendly parameter tuning
• Tag-based collision detection system

Design Patterns

• Singleton: Game and audio managers
• Component-Based Architecture: Unity's component system
• Observer Pattern: Event-driven health and state changes
• State Pattern: Character states (menu, gameplay, level transition)