I anwser why the people look like they have modern haircuts and looks. Because they do as Xenonuauts 2 is set in alternative history where the Soviet union hasn't collapse ( maybe the aliens have something to do with that) and such the cold war is ongoing up until 2018.
Also I believe officially the Xenonuauts are consider a terrorist organization, so human forces will fighting against the Xenonuauts as well.