This study produced three important contributions. Firstly, we presented a mobile AR exergame. This is significant because up to date there are only few exergames that utilize the affordances of augmented reality. Secondly, we utilized Unity 3D to implement a version of Calory Battle AR. In the process we analyzed the challenges of developing a mobile AR game and how Unity 3D can solve some of those challenges. These experiences can be beneficial to other AR game developers who seek to facilitate AR game development process while enriching AR content visualization and interaction. Thirdly, we presented the results of a usability evaluation comparing two versions of Calory Battle AR. The usability evaluation drew interesting results such as defusing with a finger is more comfortable than defusing with a multitool. These results indicated points of success and failure which form the basis for future improvements, but a deeper comparison should be done in the future to understand underlying reasons for improve usability