That was Duke 3D Before that Duke Nukem was a platform game (2D). Wolfenstein was the first first person shooter that I remember. After that i'm pretty sure it was Quake or Doom. For some reason we didn't try to have a LAN party until Duke 3D came out.

am very well aware. doom was older by far, but duke was just better for multiplayer. until we started with heretic 🤣