Some of the changes that I remember that were greatly appreciated were:
-Adding a counter for the turns that Iron Will is active, since before you just had to guess and if you guessed wrong, you would be punished by falling prey to a succubus temptation.
-Making the sex scenes, like the one for the leafhair succubus, much shorter, since before it would drag for so long thanks to the transitions each time the MC would cum.
-Changing the common enemy that you encounter on the map from a succubus to a demon plant, which makes sense lore wise.
-Adding animations (which in this case I would also thank fr5ut who started doing this in his free time and later got in touch with Zion and they partnered up)
-Getting rid of the JoJo references, which didn't really belong in this game
-Hiring a voice actress, which is now only present with Argeia (the white demon), but will be added soon to the first general Dahlia.
-Being able to use iron will during a sex scene either if you surrender at the beginning or if you defeat the succubus, which lets you take a small sneak peak if you don't want to have a game over.
-Fixing the bug where you were not able to open the menu if you played through the prologue.
-Growing stronger by obtaining runes instead of by leveling up, since, as already explained by Zion, you are already among the peak of what a human can do, which also makes sense story wise.
-The above point also changed the way you would find money in crates and use that money to learn magic, which was weird, to instead using your money to buy items (as of now) and changing the magic to skills which you learn after each fight.
