Energy communities are widely studied from various perspectives, especially in the context of geopolitical events of recent years, when humanity is faced with the need for urgent solutions to mitigate climate change and alleviate the crisis of energy resources. Although citizens’ interest in the use of renewable resources has gradually grown, energy policy support measures for more active participation of society in the implementation of energy efficiency measures are still being implemented with variable success, especially through mutual agreement. Serious games are a rapidly growing tool for awareness and collaboration on a single platform for gamers seeking solutions to energy resource optimization issues. The main focus of the article is on the opportunities offered by a newly developed simulation tool for promoting the development of energy communities and the experience gained by its users. The tool’s description and simulation results provide new information and knowledge for those working in the serious gaming field. The proposed solution promotes the development of new methods (tools) for decision-making processes based on serious games. This study uses a multi-player simulation tool to enable the modelling of scenarios for energy efficiency measures for apartment building block residents and energy community target goals for decision-making decisions. User experience and game mechanics were tested on a pre-selected group. The results indicate positive feedback, including a practical application for both energy community and professionals, and provide valuable recommendations for further research and improvement of the tool.