Story is very unique and fully voiced; MC is not the main focus of most of the stories unlike most idol games. In fact, other than to Kei and Heath, the MC has very little importance to the other characters (MC is related to something big in terms of the plot but we don't know what it is yet). I like the fact that the game focuses more on developing the characters rather than having it about everyone trying to get the MC to fall in love with them. There is A LOT of drama that goes on between the characters and there are a lot of mysteries involved that have yet to be known. For other idol games like IChu, Bpro, and Tsukipara, I couldn't be bothered to read the story but Blackstar is really dramatic (and its funny when the cast members have cat fights lmao). It starts out after the original owners of Theater Starless (among several other people) mysteriously disappear and then the theater gets robbed by some people who broke in. Like, WHAT??? What a while way to start. I can't help myself getting so excited over reading the next episode, it's honestly a first for me. Just as a warning, the story is very very shady and dark and in some instances lowkey depressing so it's not for people who like happier things like most idol games are like. For me, that's kind of why I like it so much because it's more realistic (minus the wacky situation and the fact that there may be some kind of crime group related to it...?). I like the fact that it's so tense and everyone is so anxious all the time because it makes me wonder what's going to happen next and there are A LOT of things that happen that is totally unexpected. But I'm aware it's not everyone's cup of tea, so if you like happy stories you might not like Blackstar's story.
The songs are alright. Very much on the rock side. If that's your thing you're gonna love the songs. Personally, I like the usual "idol songs" that are more upbeat so I really like Team P's songs, but the others are mostly rock which I don't prefer as much. They aren't bad at all, it's just I don't find at least 1/3 of the songs stick out to me :/. Of course the main song (theme song?) BLACKSTAR was really good. After Hatsukoi, it's my favorite. Something I find interesting is that the songs are not sung by the voice actors, but by professional singers (such as Ide Takuya, Fujita Rei, Kobayashi Taro) and Utaite (such as kradness, Stungun, Shakemi, ajikko). The only thing I wish though, would be that they chose singers for some of the characters that actually resembled the character's voice. For example, Rindou has a low voice but his singer, ajikko, has a high voice which is not bad but I also kind of want to hear what it would sound like if Rindou was singing it since people don't normally have such a wide gap between their talking voice and singing voice^^;
There are two types of gameplays in the game. One is the "Rehersal" (I may have gotten the name wrong as I don't have the game open with me at the time of writing this) mode which is a lot like how in Enstars or A3! you don't really do anything and just tap tap tap to get stuff; except unlike those games I just mentioned, the animation in it is not as fancy (since it isn't really the main part of the game I guess). The benefits of doing the lesson is that during the performance you will get a boost (higher score) if the levels of the characters in your team are high in the lesson. It will also improve your accuracy during the Cheer mode of the performance (people suggest around level 15 for every member in order to get a good score). If your levels are high, you may even get a higher score in Cheer mode than playing manually. Some events also have relationship stories between 2 members whose relationship bar can be increased in the rehearsal mode during the event. While those stories are not important to the main story, they're important in learning more about the characters involved and, of course, their relationships with the other cast members (you also get dias from reading the story). Finally, in the recent events, some of the main story unlocking requirements have been to play the event song with members whose levels are above a certain amount (those ones are a killer;;).
The second type of gameplay is the "Performance" mode which is the rhythm game. Within performance mode there is a "Rhythm mode" and a "Cheer mode" which is autoplay of the rhythm mode. The notes are vertical, which may be difficult for some people but in general the music gameplay is rather simple (of course there are multiple difficulties and you can change the speed so that can make it more difficult for you if that's your thing). I like how in some songs, the notes make the shape of something significant in the song at the moment. For example, in the song Daken, as the singer says "Team K", the long notes come together in the shape of a K; in Hatsukoi, there are heart shaped long notes; and in During the Demise, as the line 救国の剣 (The Sword of Salvation) is sung, the long not is in the shape of a sword. There is no fancy background with characters dancing (in all honesty I don't even know what the SD character designs in the cards are for because you only get to see them at the beginning and end of the song;;) unlike other idol rhythm games which is a shame. For beginners, I find that getting high scores (and therefore more points in events) is really hard (getting points in events is pretty hard without event cards in general) and it also doesn't help that the gatcha rates for 5stars is really low (and in event gatchas, a 10play guarantees at least one 4star but not necessarily the event 4star if there is one). However, you can get decent scores with an all 4star team if their stats are maxed out (I suggest to increase the "chance" levels so you get more items to level up cards during a performance). Apparently using paid dias doesn't increase the rates in the gatcha either ;-; (not a good way to encourage people to pay Donuts...). Getting the event 5stars are not too difficult (except in seasonal events they require 3 times as many points) and at the end of a season (so far only season 1 is finished), there is a big event which brings back all the main story events so you can finish unlocking stories you didn't unlock during the original event. In those events there are point rewards that can be exchanged for event reward cards and are really easy to obtain (I managed to get all 5 copies of the Kokuyou/Akira , Yoshino, and Sinju/Menou cards; 4 blank cards (for versus type events) of the Kokuyou/Mokuren card; and a copy of the Rindou/Menou card. I could have probably gotten more but I got lazy near the end of the event lol). Unfortunately there currently are no ways to obtain copies of seasonal event cards after the event is finished (hopefully they'll bring them all back in an anniversary event!)
The art is REALLY pretty. I found out about this game after Tsukipara announced they would be stopping services (and later on Bpro as well ;-;) and the art was originally what attracted me to the game. The cast members are so pretty, and there are multi-dimensions in the shading (i.e. it's not just a base colour and then a shadow layer on top). I'm a big fan of Kokuyou, Yoshino, Kasumi, and Yakou. There is also a character who's gender is cannonly "unknown" (性別不明 is what is said. There are probably many English labels you can give to this character based on it such as non-binary but literally it says "gender unknown" and does not directly translate as non-binary so I will not say) (Mokuren) and one who is (heavily hinted to be) bi with a preference for men (Qu), which I find is unique, because LGBTQ+ is not a widely spoken topic in Japan and genuine media (not BL/GL(yuri) which tends to be unrealistic) related to that topic. The cast member's stage costumes tend show a lot of skin (with the exception of Mokuren who always has their body covered) lmao (Kei has a shirtless 5star sdfsd).
Overall, I personally LOVE this game despite even though there are many things that could be improved. Through the stories the characters become likeable, then dislikeable, then likeable again, and it's honestly an emotional rollercoaster. For me, it was the art that attracted me to the game but it was the story that kept me hooked. I find that the story is the most interesting part of the game so if you don't understand Japanese and can't be bothered to translate (or look for people who have translated it) the game may seem mediocre to you (although a lot of good male idol rhythm games have been stopping services recently). The stories give you a lot of exciting (?) information (that people love to make memes out of especially in the JP fandom). I play the game for the stories
Tldr: The story and visuals are the best part of the game, the game play is rather simple (but still entertaining), songs are good if you like rock, not very generous to beginners
Sorry this ended up being very long^^;