Traditional multiplayer gaming faces challenges like hardware requirements and installation barriers with developers needing to synchronize state across computers, while centralized cloud gaming introduces infrastructure costs and potential latency. This thesis presents GameBeam, a novel, fully decentralized peer-to-peer (P2P) game streaming framework designed to overcome these limitations. GameBeam enables installation-free browser access for guest players and simplifies multiplayer development by streaming the host's game instance. This research details the design, implementation (including a Unity SDK), and quantitative evaluation of the GameBeam architecture. Performance analysis facilitated by a custom automated testing framework characterizes GameBeam's capabilities under various configurations. The results demonstrate the feasibility of the decentralized approach, achieving low mean end-to-end latencies (around 50-51 ms in baseline tests) without dedicated servers. The evaluation quantifies host resource utilization (highlighting GPU and hardware encoding impacts), network bandwidth consumption, and scalability limitations, while confirming high streaming quality. Collectively, these findings indicate that GameBeam is a viable alternative for specific scenarios, with contributions including the framework design, empirical performance data, and open-source tools, providing a foundation for future research in decentralized real-time applications.