1. There is no "non-shadow version" - that is just the style, for easier production, not a censorship. But I get what you are referring to I guess. In "Ethereal Legion" by Acid Style were 2 versions of CG, with shadow and non-shadow versions
2. Game is pretty short, so I don't think you need cheats. On the dedicated thread on F95pzone I pinned the save file and instruction where to put it(I can't post direct link in reply, sorry), guess I should pin it on other platforms as well. On Itchio on my page, you can find the link to my boosty where I'll post save file too