First. Turn the game into a single FPS that is not necessary for the pvp, make your own version of Battlefield Vietnam, add vehicles, strengthen AI, expand the map, or real strategies that appear in history, etc.
the second. Design level system and tasks. The population of this game has already supported basic game plays such as killing people and capturing the flag; to allow players to go online and have something to do, since the price cannot do 3A, it can be used to display illustrations, historical descriptions, testimonies of North and South Vietnamese, and other historical collection elements. I don't care if you raise the price or sell me DLC, I just hope Vietnam themed games trendy from you. I'm tired of the near future and WWII