Shin Ringetsu

What's the difference between Shin Ringetsu and Ringetsu: The Animation. It seems like both of them have the same protagonist and heroin.

Shin Ringetsu is a rewrite of the Original Ringetsu, where the former fiancee got "revived" miraculously while the original one is dead from the start, and she wasn't even "drawn" in the original...

Pregnant sex is more prevalent in the later (Shin).