If anyone wants to take computer game design as his/her as a profession, then the knowledge of Computer Graphics is most useful since there are so many applications of Computer Graphics for the purposes of "Computer Game Designing".
So the initial skill of "Geometric Modelling" and "Advanced 2D Computer Graphics" is needed for Computer Game Design purposes.
Hence, we should focus on some topics of Computer Graphics that are needed for object art, designing, visualizations, and transformations.
So 2d & 3D transformations, Anti-aliasing techniques, image processing, and some drawing algorithms can be focused to go ahead with expected desires.