Project Management (PMgt) is a discipline that demands both technical expertise and advanced soft skills. While Serious Games (SGs) are increasingly used to support experiential learning in PMgt education, most existing games are limited by short duration, single-player modes, and narrow focus on cost and time management. In response, we developed Titan Mall, a multiplayer, collaborative and competitive SG simulating the bidding phase of a real-world construction project. The game assigns specific roles to players and integrates a dual-layer structure combining Agile and Waterfall approaches, offering a realistic and immersive PMgt experience across multiple Knowledge Areas (KAs). Students were also encouraged to make responsible use of AI tools to support their work, reflecting real-world practices. Initial testing with Master's students revealed strong appreciation for the game’s realism, teamwork dynamics, and competitive engagement. However, feedback highlighted the need for better workload balance and more structured performance evaluation. Future developments will focus on optimising workload distribution, incorporating intermediate milestones, and refining performance evaluation tools. By addressing key gaps in current SGs—namely collaboration, competition, extended duration, and KA coverage—Titan Mall offers a flexible and scalable framework for advancing PMgt training through applied, team-based learning.