
Former Rockstar technical lead Obbe Vermeij has said early stabs at GTA 3 multiplayer included a basic version of a deathmatch-style mode.
Of course, GTA deathmatch goes all the way back to the PC version of the original 1997 title, and was continued in GTA 2, but GTA 3 never got official multiplayer support. We've also known for a long time now that Rockstar originally planned to add multiplayer to GTA 3 but ultimately decided to dedicate those development resources to Vice City.