Doddler

For those that have to use a locale editor, what language and locale is your OS set up on by default? Trying to track down why the locale emulator is required and can't seem to reproduce the issue.

The encryption is trivial to bypass... gotta love how easy it is to decompile c# IL code. The actual script content is oddly in csv format.

Spoilered, but it's not really much of a spoiler.

It seems I've been mistaken, it is ending 8, "Memories of That Day", which triggers the second playthrough and change in title screen. You can only get the normal (and true) end on second playthrough still after getting ending 8, and the true end additionally requires you to have seen ending 2 "To search for Toko..." and not having slept with Ayumu or Yukiko. The true end however does not require the normal end.

It may not be clear if you're following a guide, but you must start a new game in order to get the true end, loading any of the old saves won't be enough. Once you have the normal ending (and the title screen changes), you should be able to obtain the true end once you start from the very beginning.