Ask for expert advice: why can't we continue the new game after the end of life (the end of America) by selecting the difficulty in the menu? All the collected guns are gone.
Continue the new game+? That's Bi Zhoumu, which integrates weapon modification and vitamin skills, but only supports Bi Zhoumu with the same difficulty, which means that the vitamin skills of Bi Zhoumu in transforming firearms with difficulty cannot be passed on to survivors. If you want to choose the difficulty, you can only choose to start a new game in the menu.