A little background, I am a fluent Japanese speaker and had no trouble navigating the game and jp youtube videos and forums for tips, so none of my opinions are affected by any language barriers. I played non-stop since release and has decided to uninstall today. writing this so casual players / non-whales can be aware of the major flaws of this mega hit which the die hard fans aren't talking about:
graphics - blows old gen gacha games out of the water, but these days there are open world gacha games out there so not top of the line, but still, impressive enough
sound - personal preference here but ugh I hate idol songs, as for bgm it's pretty generic
story - the character stories and main story are good, really good, better than its own anime and honestly funnier and more moving than any of currently airing seasonal animes. looking back now, it's the only reason I played for as long as I did, I uninstalled but honestly I'd probably still dig up videos of new story/character chapters when bored in the future
gameplay - this is the big one, the biggest one. so first things first, at the time of uninstall I'm Class 6 in arena and my campaign success rate aka winning URA FINALS is like, 99.9%, I'm about as high ranked and successful as a f2p player can hope to be, so I'm not calling it frustrating because I don't know how to play. so here we go:
1) Gameplay is luck-based. Oh God it feels good to say that out loud. Don't let anyone tell you otherwise. Drives me crazy watching the fanboys on jp forums insist that it's not. the status distribution is random, the events are random, the important events rewards are random, AND THEN, during the race, the skill activation is random, the status performance is random, the position is random (yes even with reposition skills because again, skill activation is random), oh and the uma musume race condition which applies a global buff/debuff to their whole performance during the race? Random. You can literally do everything right during a campaign and the game can slap you with 4 bad condition events consecutively, ruining your hope of getting a good stats run at no fault of your own. HOW is this not a luck based gameplay ffs it's the definition of complete chaos. which brings me to the second thing.
2) As of right now, we don't Really know what the gameplay is. That's right. I see other reviews have explained what power and stamina and so on are but those are not accurate, no one knows, in-game descriptions have been proved by jp players to be inaccurate, there are a bunch of theories flying around and here's the cherry on top, the fanboys are treating this like a good thing. yeah. "wow this game is so deep this is why I can't quit! xd" That's not deep, that's the game designer not doing their basic job. In-game description of character stats need to be, well, descriptive, and accurate, the game is making players spend hundreds of thousands of stamina to figure out how these stats actually work. Imagine if a game didn't use HP, MP, stamina and just made up a bunch new concepts for character stats and didn't explain what they did, that's what uma musume is like right now. Cygames has a lot of good will, and honestly for good reasons but watching people defend this is maddening.
3) Gacha. Brutal. And yes I realize they just did a free 5640 jewels giveaway and that still won't help, that's how brutal this is. Character and support cards separated completely. Sounds good in theory right, especially for the FGO players out there who's tired of seeing mapo tofu on their character PU? Uh-uh, not here. Why? Because support cards are EVERYTHING in this game. You don't get stronger by getting new characters, you get stronger by stacking support cards so they reach max bond levels faster and give out more points during training. What does this mean for non-whales? It means you have to make a choice. Either give up on new characters completely, stack support cards so you actually progress as a player, or pull your waifus and see little to no progression in your gameplay until the game is out of service. It's a gacha game, pulling for characters you like is 99.9% of the motivation, and this gacha system forces you to give that up if you want to progress. Yeah, this really killed my mood of continuing as well.
4) the daily chore of this game is A LOT longer than other gacha games and not any more interesting once the cloud clears and you figure out the pattern of raisi ng the uma musumes of different types (long distance, short distance, nige, senkou, etc etc), it just...all becomes the same thing every day. You might be thinking, well isn't that every gacha game, and you're right, in every gacha game after reaching endgame of the current update you're just doing the same dailies every day but, the dailies in uma musume take way too long. I think it's 5~6 campaigns you can play daily with natural stamina regen, and that's at least an hour for me, much longer if you take in the thinking and planning. Like I got other games to play and I need my gacha dailies to take less than 20 minutes per game.