In this scenario, a combination of Server Load Balancer (SLB), ECS, ApsaraDB for RDS, and Auto Scaling is ideal. SLB distributes incoming traffic across multiple ECS instances, ensuring high availability and reliability. Auto Scaling automatically adjusts the number of ECS instances based on demand, managing costs efficiently by scaling out during peak times and scaling in when demand decreases. ApsaraDB for RDS provides a managed database service that handles increasing database demands without requiring complex manual scaling. This portfolio is optimal for fluctuating gaming traffic as it ensures load balancing, scalability, and cost control.