Talk:Monster Girl Quest: Paradox/@comment-5638713-20180219173531/@comment-4790504-20180219175641

It means that you won't be able to obtain the story completion achievement from the current playthrough, if you choose to enter and collect any of the super weapons from the current version of LoC (2.20).

This restriction carries over onto NG+ as well, so you won't be able to get that achievement in Part 3 if you decide to keep playing with that save file. Either keep two separate saves or hold back from playing LoC for now...or start a new game once Part 3 comes out.