Work-around for categories in the Mac App Store
This isnt a question but a simpler work around (in my opinion) via a link and use of Quick Links section.
1) Go to this link→View Games in Mac App Store then click the link the picture below:
2) It will launch the Mac App Store and there will be section (that magically appears):
3) To choose other categories:
I say magically as pressing the back button will cause the quick links section to disappear.
The only caveat is that you have go through these two links to browse categories every time.
It works on my iMac mid-2011 model, High Sierra. Hence, it should work for any newer macs running on the same OS.