All of these items should be completed once the main original game is playable from start to finish on PC with no crashing or major issues.

PC graphics settings - higher resolutions, anti aliasing, etc. Any rendering improvements but make them all optional, use Nightdive remasters or things like the Quake 1 remaster as a reference of offered features.

Co Op - find a way to implement local co op for the game on the singleplayer levels. The game already has local split screen multiplayer, but we'd want to extend netplay at least for LAN so that two PCs could run the port and play co op together. 

Deathmatch - use the co op netplay to make deathmatch / regular multiplayer playable across 4 instances of the PC port on a local network