The initial stage of the learning programming process is an arduous task. Novice students have to simultaneously learn the syntax of a programming language, understand the algorithmic logic that each program is based on as well as comprehend the basic concepts of the programming principles. The problems students are faced with become even greater when teachers employ complex environments with minimum graphical facilities instead of user-friendly educational programming environments. At the same time, constant technological developments indicate that the global market will continue to require highly skilled computer programmers; thus, the usage of advanced educational environments to properly train future professionals is essential. This is one of the reasons why a new type of technology called Serious Games has started raising great interest in educational settings. Using serious games in education combines increased motivation of students with the incorporation of course materials within the games' tasks. The aim of this paper is to apply an educational Massive Multiplayer Online Role Playing Game (MMORPG) named CMX in university settings and evaluate its efficiency in successfully teaching programming elements while entertaining and engaging students in an interesting environment. The game is applied in two groups of students already familiar with basic computer programming concepts and it has been populated with units of learning regarding arrays in the C programming language. Both groups engage in and interact with the game's environment, Senseis, tasks and other players and we record their behaviours during these activities. Additionally, we monitor in what ways the game facilitated in students' comprehension of difficult concepts and enhanced their ability to program code using the C programming language. The paper presents the implementation and elaborates on the game's evaluation based on specific axes, such as players' performance, game's difficulty, game's entertaining elements, players' knowledge and skills, game's performance and CMX as an educational game. The case study was evaluated following methodologies used in related works. The results indicated that the majority of the students were positively inclined in re-using CMX for learning additional computer programming elements and were satisfied with the game's scenario because of the variety of activities they encountered. Finally, the paper presents future work that aims to enhance and expand on the game's features in order to increase students' performances.