To start off, I've only played this for few days, 5 days including today. I hope you can imagine what you will experience as far as my 5 days.
I actually forgot to give my review on some basic contents. The storyline is mediocre, typical cute girls in action, underage highschooler and are at war. Sound and music quality are great, I talk about it's quality, whether it's enjoyable or not, it depends on some people and their moods. Graphic? I almost never rate game's graphic, because it's not a value for the game to be rated high or low, good or bad. Gameplay is decent and enjoyable, but become boring and tiring at some point. Find out for yourself, the game is good and who can resist such cute underage school girl? Haha, what a creep remark I just write.
[Too long didn't read]
Just realized my review was really long and not readable at this point. So, this game will become really grindy as you reach mid game, and will continue to be like that in the long run. Rewards are not as generous as it gives you the first time. Daily and weekly mission rewards hardly give you any rewards you will mostly need. This game aren't even enjoyable to be played casually. Hey, it's Yostar, show some respect. Haha.
[My experience, how biased]
My first experience with this game is not good (skip this paragraph, because it's long and not important). I somehow unfortunately played the game 1 hour before maintenance (not today maintenance, the one before that). Bad thing is I didn't skip prologue and tutorial story, so 1 hour was spent on downloading additional data and prologue. Waiting for the maintenance to be done but how surprising, they prolonged it from 17:00 to 21:00, then prolonged again to 00:00 (JST). The excitement all is gone and that really upset me, I posted a note regarding that matters. That's my first bad experience with this game. Finally able to access the game after that day, kinda lose the spirit to play but hey, Yuuka is there waiting for me. So yeah, she's the adorable underage that I'm pretty sure everyone loves.
[Wow, how generous!]
Game itself is mediumly fun, you got rich of rewards for starter and you even get free 10× pulls after the tutorials. Clearing first chapter and some of tasks, I got a total of 9.000+ diamonds (because I didn't spend any at first). Well, I then tempted to gacha till I spent most of my diamonds left me with only hundreds left. Per 10× pulls, it costs you only 1.200 diamonds (quite low on numbers aren't they?), but hey, if you get a dupe, you didn't get their shards and instead the dupes exchanged to "Shard Shop currencies" where each shards costs you 1 with max 20 purchase and then restocked but the prices go up by 1. Looks cheap, but take a note, they are actually not. Oh right, at Shard Shop, you'll be able to buy a char shards if you acquired the char. If you don't have the char, then that char shards isn't available there.
[Star-up and shard system for characters]
So, starring-up a char to 2 stars cost you 30 shards, to 3 stars cost you 80, to 4 stars 120 I guess (I don't remember). Hey, I spent all diamonds on gacha, so I must've have plenty of that right? No, 1 star dupe give you 1 shard currency, 2 stars dupe give you 10, and sorry, I haven't got any 3 stars dupe. So, yeah, game is actually not that generous. There are currently 3 ways of obtaining shards that I know of:
1. Shard Shop.
2. Arena Shop.
3. Hard/Elite Campaign rewards (it's not guaranteed, limited 3 times daily with 1 chance to refresh the limit once per day).
Then, how long would it take for you to star-up one char from 2 stars above to the upper or even max stars? Probably would take weeks or month for 1 char to be 5 starred.
[Campaign battle and others]
As you progress through the campaign, the difficulty are getting harder and harder. It's not the typical hard where you can clear it with just lvl up and maxing equipment. You can't even refine your equipment to advanced level without required materials that's hardly to obtain unless crazily grind enough.
[Battle system and perfect score]
This game is super grindy for the long run, not to mention it will only getting more difficult as you hardly gain necessary resources for skill upgrade and equipment refinement. Each stages require you to beat all of the nodes with S rank and limited turns in order to have 3 stars, but you need to be able to complete the nodes under 120 seconds with no death in order to achieve S rank.
You have to understand the battle mechanics, there are a table of explanation of what each units effectively fight against which unit types. I don't understand Japanese and too lazy to translate it even though I have the ability to access the required tools to do that. In other words, you will need several different units in your squad to be able to efficiently defeat them. You can view what type of units of enemies are on the upper right button.
[Chars and skills]
As I've mentioned, you need to understand each chars skills and passives to have better results in battle. Take a note, you will hardly have enough resources to upgrade chars skills and passives as it is hardly rare to obtain because no gurantees and if you manage to obtain, you'll only get it around 1 or 2. Currently, all I know where you can obtain the necessary materials for skill upgrade is from "Schedule" which you'll unlock after completing stage 2-5 (if I remember correctly).
[Schedule level, points, and it's system]
There is a place where you kinda practice with some of your students and you'll increase intimacy with the chars if you have them and you'll get points to upgrade the place level, each practice you'll earn 100 points. Yes, there are 4 places, each places have level. Everytime you level up, you'll get reward (I don't really remember what the level up reward is), but you can only do it 3 times a day with additional one time if you buy the tickets from shop. After every practice, there is a chance you'll get skill material, but my highest was only 2 in one practice and most of the time, I didn't get any. Have fun with your students.
[Hunting, I guess]
There is this mode where you can obtain exp papers and gold. In there, many stages are there for you to clear, but I believe you'll only be able to clear up to 3 stages as you're still weak. Fret not, the rewards there isn't that bad, it's quite decent for the gold. As for exp papers, I highly advise to obtain them through hard/elite campaign stage for the time being, but if you needed that, just do it.
[Equipment upgrade and refinement]
Equipment here are not unequippable, once equipped, it's attached to that char for life. Don't worry, you only need to obtain one and then it's upgradable until the tier reached the highest tier possible. Oh no, you can't refine the equipment because the material needed is nowhere to be obtained because you are still newbie and haven't unlocked the place to obtain the things. Well, just play, I guess.
[Daily and weekly missions and their rewards]
Daily and weekly mission rewards isn't really that generous, you will hardly gain any more diamonds to spend on gacha after those sweet newbie rewards are all claimed and spent. So, spend your diamonds wisely. Oh wait. Not just the diamonds, the rewards isn't even the one you will mostly need and the amount of that reward is generously low.
[Disaster, at least for me]
Can't refine equipment, stuck on chapters, how to get more powerful? I'm power hungry! Level up my friend, the higher the enemies level are, the more power you need to achieve perfect 3 stars. So, I suggest to clear them with 5 levels or more gap or else, you need to star up characters to be able to grow more powers. Didn't I say it's actually expensive and need at least a week for 1 char to reach 4 stars? Yes, that's what the gacha is for!
In other words, if you are all for super grindy games and have the patience, this game is perfect for you to enjoy. If you don't have the patience but still all for super grindy games, then this game will become super gacha oriented.
Yes, this game is too overrated. What's the point of playing a game that appear to be sweet and generous at first but exhausting and boring only after a few days? Many people are too focused on how easy or how generous game developers about gacha. Then, some of people are a fan of Yostar so it's not surprising if they tend to forget the important point of a game being enjoyable. People are just too addicted to gambling, that's why most of them only care about gacha, presumably only to show off their luck to others, but hey, I mustn't judge a culture.
Well, I just want to say that some people should be more critical about the game system and it's mechanic, not just too focused on the gacha and it's newbie rewards. I've played too many games that have similar sweet generous on surface, but ridiculous and hell grindy deep down. Grindy game is not that bad, it's just time consuming and in the end, it'll just tiring you because it gets repetitive and a waste of time when you reach to the point of getting bored.