New Features:

1. Player and Zombie Mechanics:
   • Zombie Types: Expansion of zombie types (normal, blue, brute, speeder, ranged, miniBoss, boss) with distinct attributes such as health, damage, speed, and special abilities.
   • Weapon Types: A diverse set of weapons with distinct patterns (single, spread, rapid, explosive, etc.) was created, allowing for unique gameplay styles.
   • Passive and Active Abilities: Introduction of complex player abilities such as sprint, shield, stealth, and various passive traits like regeneration and vampirism.
2. Scene Design:
   • Dynamic Environmental Elements: Trees, buildings, and additional environmental details (rocks, dirt piles) were implemented for aesthetics and gameplay interaction.
   • Health and Stats Tracking: Health bars and stats display were added for both the player and zombies, providing more feedback during gameplay.
3. Game Flow and UI:
   • Start Menu and How to Play Screens: An improved start screen layout for new players, along with a detailed how-to-play section.
   • Pause Screen: A pause functionality that allows players to resume or pause the game comfortably.
4. Leveling and Progression:
   • Leveling System: Players can gain experience from kills, leveling up for new upgrades and abilities as they progress.
   • Unlockable Characters: Unlockable characters based on performance, such as the ObesePanda, Gibby, and Annihilator.
5. Randomized Events:
   • Controlled spawning of zombies, including mini-bosses and bosses based on player level, adding variety to encounters.

Fixes and Improvements:

1. Performance Optimizations:
   • Cull Distance Management: Implemented a mechanism to adjust the visibility of scene objects based on framerate; optimizing performance for lower-end devices.
   • Active Particle Management: Fixed the management of particle systems, ensuring proper cleanup and maintaining performance.
2. Player Collision and Health Management:
   • Improved mechanics for player interactions with health kits and collision detection with zombies and trees.
3. Ability Cooldowns:
   • Added cooldown management validation for active abilities to prevent them from being used outside their allotted time.
4. Weapons Handling:
   • Streamlined weapon switching and purchasing mechanics to enhance in-game experience.
5. User Interface Enhancements:
   • Improved health bars' responsiveness to changes in health and providing immediate visual feedback during interactions and combat.
6. Code Organization and Clarity:
   • Refactored to create more organized and maintainable code, allowing for easier updates, and enhancing clarity for debugging and future development.

Identified Bugs (Hypothetical Fixes)

1. Spawn Position Validation: Fixed logic to prevent overlap between spawned trees and zombies to avoid gameplay interruptions.
2. Active Ability Timers: Ensure that active ability duration and cooldown mechanics are correctly tracked to avoid unintended benefits for the player.