Well my friend, that is a quite nice question to a simple answer.
First, did you extract all the game RPA including the versiviondlc.rpa that someone shared above?
If not do that first.
Now adding button to mainmenu would be too complicated and somehow the quickmenu will not appear either.
So just edit the script.rpy and find this code:
View attachment 1784795
and add the code below:
Code:
menu:
"Original Game?":
jump first_scene
"VersiDLC?":
jump dlcversa
so that It will look like this:
View attachment 1784797
remember, Indentation aka space behind the text is important.
Now, you are done, play the game, after character naming, the menu should appear and hwalaa enjoy~
oh oh, and since we are using the old version, there is a transition that doesn't exist.
So go over to versi.rpy that is inside versidlc folder
CTRL+F
and find:
Code:
$ renpy.movie_cutscene("images/CG/elipsis.webm")
Erase all those codes.
And you should not face any error.