The era of the 3D shooter was inaugurated in 1992 by the shareware release of Wolfenstein 3D by id Software, for 80286-based DOS computers. It wasn’t until this year though that the game was backported to the 8088, the chip the original release of the IBM PC used, and CGA cards. The port was made by James Howard, who showed it off in a Twitter thread. Rees at RetroRGB wrote an article on this “updated” version.
While the monitor colors for CGA are pretty harsh on the eyes, the code also has support for CGA’s little-known 16-color composite output, as well as Tandy graphics and monochrome.
WolfensteinCGA source code repository (GitHub, requires shareware or commercial Wolf3D data files)