Since the emergence of bitcoin, its underlying technology, called blockchain, has attracted a lot of attention and interest in both research and industry communities. Blockchain was designed to be a decentralized architecture and resistant to malicious modification of data, featuring secure, traceable, and verifiable data. Although there are also some criticisms of blockchain's effectiveness and applicability, many pilot applications have been appearing, demonstrating the necessity of further research on blockchain technologies. This paper presents the motivation, design, and current prototype of our experimental work on developing a decentralized online game platform based on blockchain. This platform was designed for non-real time online games. The blockchain platform can bring online games several advantages such as resistance to DDoS attacks and protection of game data integrity. Moreover, it could also be used as an experimental platform for research and development work on blockchain technologies and applications.