You can really tell multiplayer was added to Doom in the last month before release given it has no GUI to launch and instead involves DOS commands like sersetup.exe -player1 -19200 -com1 -episode1 -skill 4, and none of this is in the print manual as far as I can tell.
And yes, the space between skill and 4 (Ultra-Violence) is intentional. Unlike all the other ones, it doesn't work without it.
EDIT: As I was reminded by @nazokiyoubinbou , there is options in the setup utility, it just didn't cover my use case (needing a different baud rate than default). Whoops.








