Game engines are tools that expedite the highly demanding process of developing games. Nowadays, the great interest of people from various fields on serious games has made even more demanding the usage of game engines, since people with limited coding skills are also involved in developing serious games. Literature in the field has studied game engines focusing on specific needs, such as 3D mobile game engines or open source 3D game engines. The motivation of this article and at the same time the advancement brought by it in the field, lies in the extension of an existing framework for the comparative analysis of several game engines that export games at least on Android and iOS mobile devices and cover a wide range of different user profiles and needs. In order to validate the results of this comparative analysis a shooter game was developed for Android devices based on official tutorials of the two game engines that came out to be more powerful, namely Unity and Unreal Engine 4. In conclusion, there is not a single game engine that is better for every purpose and the extensive overview provided can help users choose the most suitable game engine for their needs.