Well, I can see there are some negative reviews, with some points being justified and some points being "I'm too fucking scrub to actually figure out how the game works", so I'll even out the scales a bit.
First of all, let's start with the story: it's alright. Really don't know what to say about it. It's not amazing, but it's not bad or even mediocre. It's just good. I don't know whether Rance matured or the writer kinda forgot about it, but it seems he's capable of multiple feats he weren't before, as in: somewhat willingly working with dudes, discuss tactics with them and even call some by their names. Oh, and they went somewhat deeper into lore and worldbuilding in this one.
Okay, now for the gameplay.
First of all, yeah - monkey orb system is kinda bullshit. Basically, in order to progress with main(for this entry) heroines and get their H-scenes, you are supposed to feed them three monkey orbs, which you get out of story and free battles. Some free battles can seem outright sadistic, but they are definitely not impossible to complete - just gotta use your noggin' a lil' bit or try it a bit later when you've grown more muscles on your bones.
This whole system wouldn't be too bad if not for two things:
1. You can't max out all the heroines even if you gather all the possible orbs during your playthrough.
2. The amount of monkey orbs you can have on your hands is limited. Hence, you can't just stockpile them and use them up all at once when you've decided on your main focus. I don't understand why that restriction was put in the first place, considering that said progress is already gated by your story progression.
After unlocking a heroine's event you get a "crab" orb. A crab orb, upon using on a character before a battle, will grant said character a double accumulation of skill points you can use for upgrading your char's stats. But here's the kicker: these orbs also cannot be stockpiled. It's really funny, because a double SP bonus is so negligeable, that you really don't lose much by not using it. But you can only have 4 in total. And if you accidentally unlock a heroine's event before using them... well, they go the the Shadow Realm, fuck you.
There's also a "magic" orb that you can use the same way you can their crustacean kin, but I have no fucking idea how to obtain them, what these are for, and neither is mentioned in the game either, I simply saw them pop-up at some point for whatever reason.
The actual gameplay is a bit boring. Typical grid-based tactical combat, but without any twist. It would benefit greatly from some more mechanics, like, I dunno, attacks of opportunity or backstabbing, but it's pretty simple: hit, hit harder with a special, occasionally aggro the enemy.
The stat system is also boring as fuck. There are lost of stats, but the ones you should actually look out for are basically: attack, HP and, sometimes, speed. Mostly attack, though. Very rarely do you need to raise some other stats, and only if you are going for some very specific build. And while you do need an exorbitant amount of points, you can complete the game easily without grinding it. The dude below who went all "hurr-hurr the game unfair and grindy" is, as I said before - just a scrub. The difficulty curves are noticeable, but not all that steep.
Hoverfort system is kinda meh also. While you don't need to grind for points that you use to buy the "ammo", because these are plentiful just from playing normally, upgrading it actually
IS grindy(random special currency drop), but not really all that needed, especially not for the first playthrough. You are supposed to stretch its progression over several NGs. After a few upgrades it's possible to break the game really easily, so it's no surprise that you don't have the fort spells during the fights that actually matter. And yeah, you can't rotate those blocks, and while being OCD-inducing - it doesn't really matter anyway.
Gold is essentially useless and is used to gacha roll for weapon upgrades and buy the armor ones. Stupid shit, yeah. Nope, you can't buy items with it, and items themselves are random drops, which is kinda cool, because it makes you adapt your playstyle, but is also slightly infuriating for the same reason.
You:
But what about sex???
Sex is fine. Covers a wide variety of kinks, too, in the true Alice Soft fashion. Almost every girl you come across has at least one sexy scene, including my fav tomboy Alkanese.
Well, that's about all I can say about the game off the top my head. It's not bad, it's not amazing - but it's pretty good. Worth playing at least for the story, and even this braindead gameplay can feel pretty refreshing from time to time.
6.5/10
Now all we have left to do is wait for another 80 years until X comes out so, while lying in our deathbeds, we can depart from this world with no regrets and a smile on our faces