Kingdom Fights

Unai Rodríguez Ferrández

January 8, 2023

Introduction

Kingdom Fights is a competitive PvP deck-building game originally developed on the Crayta platform. As the winner of the Winter 2022 Mega Jam, this game emphasizes player retention through a diverse array of card upgrades, each featuring unique behaviors and abilities. The project draws inspiration from games in the vein of Clash Royale.

As the lead developer, I oversaw gameplay mechanics and spearheaded the UI implementation using Lua, HTML, JavaScript, and CSS.

Note: This game was initially hosted on Crayta, a platform that has since been discontinued. The following sections provide detailed information and media to showcase the project.

Gameplay

Role & Contributions

In my pivotal role as Lead Developer for a game innovatively inspired by the renowned Clash Royale, I was entrusted with the comprehensive oversight of developing nuanced gameplay mechanics and implementing a meticulously crafted user interface. Utilizing Lua for game dynamics and a combination of Lua, HTML, JavaScript, and CSS for the user interface, my contributions were instrumental in achieving seamless and interactive gaming experiences.

A critical component of our success was the strategic focus on player retention, which was instrumental for our victory in the game jam. It was through my precise and efficient coding that we were able to optimize user engagement and retention, reinforcing the game’s appeal and playability. This meticulous attention to detail and commitment to excellence were paramount in securing our win and were a testament to the quality and innovation embedded within our game.

Tech Stack & Tools

Tech Stack and Tools

Engine: Crayta (Built on Unreal Engine 4)
UI Engine: Coherent Gameface (Compatible with Unity)
Programming Languages: Lua, HTML, JavaScript, CSS
Version Control: Git

Game Features

Deck Building and Progression

The core gameplay centers on creating and upgrading a deck of cards. Each card embodies a specific type of unit—be it a spell, mobile unit, or tower—with distinct behaviors and capabilities. Cards can be leveled up using in-game currency earned through gameplay. Each new level enhances the card’s stats and appearance, providing a rich progression system.

Battlefield Dynamics

The battlefield is a symmetrical arena where each player is tasked with defending three towers in a 1v1 setting. The primary objective is to eliminate the opponent’s central tower. In the event that neither central tower is destroyed, the player who has eliminated the most peripheral towers is declared the winner.

Unit Synergy and Behavior

Units exhibit a range of behaviors and actions based on their type, be it a static unit, mobile unit, or spell. Different units also have unique actions when deployed or destroyed:

Tower: Integral to the battlefield, towers automatically target and attack the closest opposing unit with cannonballs. Higher-level towers inflict greater damage. Opposing units typically gravitate toward the nearest enemy tower unless distracted by another enemy unit.
Static Unit: These units remain stationary once deployed and have various roles—either attacking or attracting enemy units—depending on their specific behavior attributes.
Mobile Unit: These units advance toward enemy territory to target and destroy opposing towers. They may engage in ranged or melee combat and could have either area-of-effect or single-target attacks.
Spell: Spells serve as special action cards that don’t deploy units but instead execute specific actions, such as freezing enemy units within a defined area or launching a volley of arrows or fireballs.

Touchscreen Compatibility

In alignment with Crayta’s debut on Facebook Gaming—which enables cloud-based gameplay on mobile devices—I have optimized the game for touchscreen interfaces. This ensures a seamless and engaging experience across a variety of devices, demonstrating the game’s broad accessibility and my own proficiency in cross-platform development.

Challenges & Solutions

Challenges and Solutions

Advanced AI Behavior Management

Developing smooth AI behavior for a diverse array of units presented a significant challenge. Units could potentially get stuck chasing unreachable targets or ignore closer, more relevant objectives. To mitigate these issues, I implemented an AI system based on a hierarchy of priorities. The primary directive for all units is to advance toward the opponent’s tower. However, if an enemy unit is within range, the AI reevaluates its target based on compatibility and attack range. This flexible approach accommodates various types of units, including those with ranged attacks, and allows for “aggro” mechanisms to override a unit’s current target.

Data Storage Limitations

The platform imposed a strict 1KB data limit per player, presenting a unique challenge for storing critical player progression metrics, such as card levels and gameplay statistics. To overcome this, I meticulously optimized our data structures, ensuring efficient storage without compromising data integrity.

Transferable Skills

UI Development: Extensive experience with Coherent Gameface for UI design, a tool also compatible with Unity, illustrates the direct applicability of my UI/UX skills to Unity projects.
AI Behavior Design and Optimization: Developed a priority-based AI system to manage diverse unit behaviors, a foundational skill that is readily applicable to Unity projects involving AI characters or NPCs.
Data Management and Optimization: Devised methods for efficient data storage within a strict 1KB limit per player, demonstrating data management skills directly transferable to Unity’s more robust data-handling capabilities.
Multi-Type Unit Management: Built a game involving different types of units, each with their own unique behaviors and capabilities. This experience in designing versatile game mechanics can be applied to Unity projects that require multi-objective or multi-character features.
Cross-Platform Optimization: Adapted the game to be fully functional on touchscreens in anticipation of Crayta’s launch on Facebook Gaming. This experience in making games compatible across different types of devices showcases my ability in cross-platform development, a skill highly transferable to projects on Unity or other game engines.
Player Progression Systems: Engineered a card leveling-up system to engage players and enhance retention. Skills in crafting compelling progression systems are directly applicable to Unity projects focused on player engagement.
Cross-language Implementation: Managed gameplay mechanics and UI through the use of Lua, HTML, JavaScript & CSS. Experience in multi-language development is readily transferable to Unity.