This technical publication presents the methodological framework and implementation results of the BIOTRAILS Serious Game, developed under Deliverable 4.8 of the BIOTRAILS project. The Serious Game serves as a digital, interactive tool designed to raise awareness of biodiversity impacts associated with consumption patterns and to promote behavioural change among citizens.The methodology integrates a constructivist pedagogical approach, gamification mechanics, and citizen science principles to link personal choices with environmental outcomes. Procedural content generation, supported by Large Language Models (LLMs), enables scalability and adaptability across diverse thematic contexts.The framework follows a three-stage process — (1) pre-game data collection, (2) interactive gameplay across value chains, and (3) post-game reflection — combining educational objectives with behavioural analytics. Results from case study implementations demonstrate high engagement, learning gains, and positive shifts in sustainable behaviour, validating the Serious Game as an effective methodology for transformative change.