Idol Manager is a terrible, terrible game. I'm not exaggerating, it's an absolute stinker of a game, though it is a game with a gameplay loop, so it gets some points.
Gameplay is incredibly poor. It's a tycoon game, but a very poor one at that. You're expected play it in just the way the developer wants you to, and it makes no sense. I've made a healthy mix of promotions and performances before releasing my first single, and despite copying the #6 of that month's best-seller, it sold 5 copies. So I thought ''Hm, maybe I need to grow slowly.'' but nope. After I made a new save, I copied that month's #1 single 1:1 and it sold hundreds.
And this is never communicated to the player. It's shitty game design, you literally can't ''run'' an idol company, you have to keep copying what other companies do until you're #1, and even then you'll regularly look at what sells and copy that, there's no way to grow on your own.
Music, is terrible. I recommend you turn the music down to %0 the second you boot up the game. It's not terrible by itself, but it's very clearly no copyright music that the dev slapped on.
Performance, well, bad. If you feel your FPS slowly going down, just save and close the game, then open it back again. For some reason, my framerate goes down by 5-10 FPS every time a new visual novel segment occurs but closing the game seems to fix it.
The writing, is overall a big ''eh''. It's like drinking soda at room temperature, it's neither bad or good, just a very big eh. It ranges from pretty decent during normal gameplay to bloody abysmal during any sort of lewd scene.
Now, the good:
The art, it's fucking great. Make sure you turn on +18 content in the settings before starting the game, because goddamn there are some good sex scenes in the game. The game is wrongly genre'd as 'No Sexual Content' at the time of this review, but I've personally used unity asset studio to confirm there are. Most of them are between you and your competitor, so make sure to choose genders accordingly.
And, that's it for the good parts really. Overall, Idol Manager is an unfun game with a boring gameplay loop, just barely held up by 'meh' writing. I do not recommend that you play this, simply rip any sprites you want from it, add the ripped images to your nsfw folder, and move on.
EDIT: Fixed a typo