At 21st century Computational Thinking (CT) is considered a fundamental skill that anyone should possess and develop from a young age. Serious games and more specifically educational games (EGs) are a promising means of introducing algorithmic thinking and programming concepts and engaging students through the process of learning. In this article, a new EG called BlocklyScript is presented. BlocklyScript aims to help students develop their CT by learning basic programming concepts, designing algorithms and correcting mistakes. During the designing phase different EGs were taken under consideration and an EG design framework was followed in order to provide a better user experience. The game was evaluated by 10 experienced computer science educators of primary and secondary schools. The positive results of this pilot evaluation show that BlocklyScript is expected to help students understand the basic concepts of CT. However, the game should be evaluated by more teachers and students in order to provide future researchers with safe results.