[EDIT] - I see in the Keen book's source git commit logs that you reviewed and assisted with proof reading beforehand, so may we assume that this is all above board and sanctioned by you?

I suppose there's still Quake 3 Arena and DOOM3 to complete the full "John Carmack" early 90s to early 2000s technical overview series.

Or maybe something with the Sega Saturn. I heard the Sonic X-treme team worked so hard to make a 3d Sonic game for that platform in the mid 90s that multiple team members had to go on medical leave!