It is a little misleading, because the original version for the PC-98 (1992) had really short endings in the first place.
The Windows PC version (1999) actually expanded on the endings, so that change was a clear improvement in terms of giving the character relationships a more satisfying resolution. They did rewrite a few other parts but, in a few words, we should remember that what made this game so popular in Japan was the romance and dating angle, not the porn.
This was never a game with a lot of sex scenes in the first place, even in the first version. In short, this is for people who want more of a galge and less of a nukige. You're there for the emotions and the dating simulation, basically. Closer to Tokimeki Memorial (1994), except with a few ecchi and adult scenes.
That's why they were able to easily make ports for the PC Engine (1995) and Sega Saturn (1996), which were also famous versions in Japan and elsewhere, even though those consoles didn't show any explicit sex.
All of this is relevant because the 1999 version was the starting point for this 2021 remake. If you check the HCG sets for the Windows version, you will see they were very faithful to what is included in the current release (as long as you have installed the patch, of course).
You can always go back and look at a couple of extra HCG images found only in the 1992 release for the PC-98, in case you feel those are needed...but in terms of the actual playing experience, this one is better in most other ways.