Worked on the DayKev/pokerogue repository to implement hazard layer handling for the Court Change move, enhancing gameplay accuracy in scenarios with multiple entry hazards. Developed a layer-aware execution mechanism that checks and applies all relevant hazard layers during move resolution, addressing a previous regression where hazard layers were not properly transferred. Applied test-driven development practices by expanding unit tests to cover various hazard layer counts, ensuring reliable behavior across edge cases. Utilized TypeScript for both core logic and testing, focusing on move-effect modeling and targeted refactoring. This work improved battlefield consistency and established a foundation for future hazard-layer integrations.