Well. Main story finished... I have my opinions on the first half of chapter 5 (and probably the ending of the main storyline).
First off: the game is pretty good and enjoyable, I like the story and the main characters and the succubuses have very creative gimmicks, the art is amazing, and the side-quests are enjoyable without being too long. So in no way I would call it a bad experience.
But let's go with some negatives of the overall game and specially the last chapter:
-The succubuses of Spring and Autumn are an absolute drag because of their paralyzing attacks, unless you consume the herb that allows you to be inmune of it's effects for five turns you have a pretty much guaranteed loss... which wouldn't be a problem if said herb was actually useful at any previous point of the game, which it isn't. Until this last two fights I spent the whole game without needing to use it not even once, so I didn't bother to buy any for the finale because I forgot those existed, so I had to make due with only five that I found around, and I was lucky I did all the sidequest before fighting the final four succubuses or I would've been locked in an impossible unskipabble fight.
-The only b-plot that managed to keep me interested was the Kein plot with the angel. The rest feel kinda like random fluff and I didn't really care for those characters (Socrates drunk on top of a mechanical golem was a funny gag, but it does not justify two hours of reading general lore of people that end up dead by the end of the game without really contributing to the main plot) which wouldn't be a problem at all and I would take it as "setting up future games" if not for the fact that the protagonist's playable story gets constantly interrupted by their interludes: you cross a random area? interlude, you defeated a succubus? interlude. You entered this area for the first time? interlude. And some of them are long.
- The red riding hood/ninja(?) succubus is kinda weird as a concept, but I guess she serves the part of stablishing that succubuses from all clans are always around an to be careful... tho it is a bit weird to showcase this at the end of the game.
-The fact that once you finish the game you get sent to the opening screen without a chance to save means I will have to re-do all of the finale once the second part releases, and honestly that feels like a HUGE drag because It is not a short while.
-I get somewhat confused by the ending, because it establishes that the protagonist for chapter 1 will be the same for the next chapters and the things that happened here will have a direct impact on the next ones... which is a mistake IMO, because it most likely means we will NOT see a resolution with the Witch or the Witch Hunter, because the survival of one implies the death of the other. It would be easier to handle if each chapter acted a bit like "jojo" in that regard, a different protagonist for each chapter, loosely connected stories, MAYBE a cameo of a previous character, but everything closes neatly without finishing open ended, so each feels like their own story.
And those are my general thoughts.
Overall I give it a solid 7/10. Several mistakes, choices I do not agree with, but a pretty fun experience nonetheless and the game knows what it is: a game about you beating boss succubuses.