The re-release is a rewritten version - an alternate continuity, in other words. I believe both versions had the same characters, though the old one was incomplete.
I actually meant the difference between the two steam versions
https://store.steampowered.com/app/2728750/Gozenyojinomanimani/
https://store.steampowered.com/app/2746960/4/
When I translate them they give the same description and a similar title so I can't tell if it's a different version of the same game or something completely different