Pong – 2D Arcade Game Clone

1. Introduction

This project presents the development of a faithful recreation of the classic Pong arcade game, implemented in Unity as a demonstration of core game development principles. The goal was to build a simple yet technically sound two-dimensional game that accurately captures the mechanics, look, and feel of the original Pong while showcasing proficiency in Unity, C#, and game design fundamentals.

Developed as a solo project, this clone features local two-player gameplay, responsive paddle movement, realistic ball physics, dynamic collision responses, and a scoring system where the first player to reach ten points wins. The project emphasizes clean architecture, modular scripting, and a smooth, polished play experience reflective of strong foundational skills in both technical and design aspects of game development.

2. Concept and Design Goals

The inspiration for this project came from the original Pong released by Atari in 1972 — one of the earliest and most iconic video games in history. Its minimalist design and simple yet engaging gameplay make it an ideal candidate for demonstrating understanding of interactive systems, physics, and player feedback within a controlled scope.

The primary design goals for this project were:

• Faithful Recreation: Replicate the visual simplicity and mechanics of the original Pong while ensuring modern responsiveness.
• Local Two-Player Mode: Enable two users to play simultaneously using the same keyboard.
• Realistic Physics: Implement consistent and natural ball motion using Unity’s 2D physics system.
• Clean Game Loop: Create a well-structured system for scoring, resetting rounds, and detecting victory conditions.
• Polished Feel: Achieve smooth input, fair collision detection, and clear visual communication through the user interface.

By focusing on these goals, the project aimed to balance authenticity with modern implementation practices and provide a foundation for future feature expansion.

3. Development Process

3.1 Project Setup

The project was initiated in Unity using the 2D template. The scene was composed of a camera centered on a playfield defined by static colliders representing the top and bottom walls. The core interactive elements included two paddles, a ball, and a UI system for displaying scores.

The initial step was to define object layers and tag key entities to facilitate collision handling and scoring detection. A simple, monochrome color palette was chosen to evoke the original arcade aesthetic.

3.2 Paddle Movement

Each paddle was assigned a dedicated controller script to handle vertical movement based on player input. Player One used the “W” and “S” keys, while Player Two used the Up and Down arrow keys. Input was processed per frame, and movement was clamped to prevent paddles from leaving the visible play area.

The responsiveness of paddle controls was a critical factor. Early tests revealed the importance of frame-independent movement, achieved through the use of Time.deltaTime to ensure consistent behavior across varying frame rates.

3.3 Ball Physics

The ball’s motion was driven by Unity’s Rigidbody2D component, utilizing velocity rather than position updates to maintain realistic interactions. When launched, the ball’s direction and speed were randomized within controlled limits to introduce variety.

Collision handling was primarily physics-driven, with reflection logic applied based on the collision normal. This created a natural bounce effect against paddles and walls. To simulate skill-based gameplay, the angle of reflection was slightly influenced by the paddle’s movement direction at the moment of contact, allowing skilled players to “aim” their shots.

3.4 Scoring System and Game Loop

Two invisible colliders positioned beyond each paddle acted as scoring zones. When the ball entered one, a point was awarded to the opposing player. The ScoreManager class maintained player scores and triggered round resets by repositioning the ball and reinitializing its velocity.

Once a player reached ten points, the match concluded, and a victory message was displayed on the UI. A simple restart option allowed players to begin a new game seamlessly, reinforcing a continuous play loop.

3.5 User Interface

The UI design emphasized clarity and simplicity. The current score for each player was displayed prominently at the center of the screen. The game over screen featured a single winner message and a restart prompt. Unity’s Canvas system was used for text and overlays, maintaining pixel-perfect alignment across resolutions.

4. Technical Implementation

4.1 Architecture Overview

The project followed a modular script architecture, with key components divided as follows:

• Players: Handles player input, movement boundaries, and speed adjustment.
• BallMovement: Manages velocity, collisions, and trajectory calculations.
• ScoreManager: Oversees scoring, win conditions, and game resets.
• UIManager: Updates score displays and manages end-game messages.

Each script maintained a single responsibility, improving code readability and reducing coupling between systems.

4.2 Collision Handling and Ball Reflection

The ball’s interaction system was designed to replicate real-world reflection behavior without introducing excessive randomness. The collision response used the following logic:

• Retrieve the collision normal using collision.contacts[0].normal.
• Calculate the reflection vector using Vector2.Reflect().
• Adjust ball velocity to maintain constant speed while reflecting direction.

This ensured consistent and predictable bounces while still allowing for dynamic play based on paddle motion.

4.3 Input System and Control Responsiveness

Unity’s default Input Manager was used to capture keyboard input for both players. To ensure responsiveness, paddle movement calculations were performed in Update() with physics updates handled separately in FixedUpdate().

A key design decision was to limit maximum paddle speed to maintain control precision while preserving the competitive pace of gameplay.

4.4 Game State Management

The ScoreManager script served as the central authority for transitioning between game states (active round, scoring, game over). When a point was scored, the following sequence occurred:

• Increment score for the correct player.
• Check for win condition (first to ten).
• If no win, reset ball and continue play; if win, display results and pause ball movement.

This structure ensured a consistent and controlled gameplay cycle, preventing unexpected behaviors between rounds.

4.5 Performance Considerations

Although a lightweight project, optimization practices were followed. Object references were cached to reduce calls to FindObjectOfType, and unnecessary physics calculations were minimized by disabling rigidbody simulation during reset states. The final build maintained a consistent 60 frames per second across tests.

5. Challenges and Problem-Solving

5.1 Collision Accuracy

A recurring challenge was ensuring precise collision responses between the ball and paddle edges. In early iterations, the ball occasionally slipped through paddle colliders at high speeds. The issue was mitigated by:

• Enabling Continuous Collision Detection on the ball’s Rigidbody2D.
• Increasing the physics update rate for critical collision checks.
• Reducing ball acceleration per hit to prevent physics instability.

5.2 Gameplay Balance

Fine-tuning ball speed and paddle responsiveness required extensive testing. Too slow, and the game lacked excitement; too fast, and control accuracy suffered. Through incremental adjustments, an optimal balance was achieved that rewarded player skill without overwhelming reaction time.

5.3 Code Maintainability

During development, an early monolithic design led to difficulty managing interdependent game elements. Refactoring into a component-based structure improved maintainability and allowed for potential scalability, such as adding an AI opponent or advanced UI systems in the future.

6. Testing and Iteration

Testing involved multiple rounds of local playtesting to evaluate control feel, collision behavior, and pacing. Observations guided iterative improvements:

• Adjusted ball launch speed variance for fairness.
• Smoothed paddle acceleration to avoid abrupt movement.
• Added reset delays between rounds for clarity and pacing.

These iterations led to a polished and predictable play experience aligned with the project’s goals.

7. Final Outcome

The completed Pong clone successfully met its design and technical objectives. It offers:

• Local two-player gameplay with intuitive controls.
• Physically consistent ball motion and reliable collision feedback.
• A simple yet polished user interface with clear scoring and win conditions.
• Stable performance across builds and frame rates.

The game captures the essence of the original Pong while demonstrating modern implementation discipline within Unity’s 2D environment.

8. Insights and Learnings

Developing this project reinforced several key insights:

• Fundamentals Matter: Even a minimal game like Pong requires precise attention to physics, timing, and user input to feel satisfying.
• Clean Code Architecture: Component-based design ensures flexibility and clarity, especially as projects scale.
• Gameplay Feel Is Technical: Achieving responsive, enjoyable gameplay is as much about physics tuning and feedback as visual design.
• Iteration Is Essential: Frequent testing and parameter refinement are crucial for balancing challenge and playability.

These lessons are directly transferable to larger, more complex projects, particularly in managing interactive systems and maintaining strong player feedback loops.

9. Future Improvements

Possible extensions include:

• AI Opponent: Implementing a single-player mode using predictive ball tracking and adjustable difficulty levels.
• Enhanced Visuals: Adding background animations, particle effects, or retro CRT-style filters.
• Audio Feedback: Incorporating paddle hit sounds, scoring tones, and background ambience.
• Online Multiplayer: Exploring Unity’s Netcode for GameObjects to support networked gameplay.

These features would further enrich the experience while providing additional opportunities to demonstrate advanced Unity capabilities.

10. Conclusion

The Pong – 2D Arcade Game Clone served as both a technical exercise and a personal exploration of gameplay fundamentals. Through the development of this project, I deepened my understanding of Unity’s physics engine, refined my programming architecture skills, and learned how subtle design decisions impact player experience.

While small in scope, the project embodies key principles of game development: clarity, responsiveness, and iterative refinement. It stands as a demonstration of practical skill in creating interactive, well-structured, and enjoyable gameplay experiences — a foundation for more complex and ambitious game development endeavors.