There's some real jank but also it's so heartfelt that it's easy to overlook the wonkiness.
For example, this is a soulslike spirelike romantasy jrpg. That's too many buzzwords you need to put some of them back.
Also, the core gameplay is a little monotonous, and a little bit incompletely explained. You won't know exactly how progression works or how the story branches until you're deep enough in that you've already made your mistakes (never leave a dungeon floor without having gotten all bonus objective orb rewards, reset if you have to.)
Also, doing a spirelike as a slow paced conventional story campaign jrpg comes with some innate problems. The luck that can screw you in a spirelike has a way harder impact when you're playing one run ever 100% for keeps.
It's to the game's credit that the things about it that are good are so good that I'm recommending it in spire of this clunky design, no guides, and the dev team having completely ghosted.
First of all, the voice acting and directing is giving 110% on what *can't* have been that much of a budget. The lead is doing that shaky breathy low voiced barely contained anger traumatic past fmc thing and investing so much energy that it carries the whole game. Most of the other voices are solid too---there's a couple duds, but they get lost in the absolute command performances from the leads.
The writing is overwrought anime edge, but not only do the voices make it work, it's doing interesting worldbuilding and the characters have chemistry. I will always, always take a script that full-sends it and ends up a little bit purple over one that is scared to show its heart to the reader. The setting is fun. The characters are fun. If you like stuff like Jigokuraku you'll have a good time here.
And the art and music are banging on at least as many cylinders---maybe more in the art's case, because the music is a bit limited in variety but the artist has popped off with some baroque fantasy backgrounds that outdo a lot of regular soulslikes. The bench made of hands is extremely good and kinda cemented for me that I liked the game.
In terms of combat and progression, everything is fine. But because the game is locked into a single campaign you can't really customize much or customize quickly in normal mode. And the way cards are given to you, you don't have a lot of control over your deck unless you stockpile certain consumables for endgame runs. You start with 20 cards, but by the end of a floor you've been sludged up with another 5, and the purpose of your deck dilutes quickly into randomness.
I have the creeping suspicion that this game might've killed the studio. It certainly hasn't gotten a ton of visibility, and that's a damn shame because it would've been a cult classic twenty years ago. It's still quite good today, and worth the pickup if anything I've said sounds interesting or you see it on sale. Don't let the generic title deceive you, Shattered Heaven knows what it's about.
Edit: Yeah, my intuition was right. The difficulty does eventually spike, at which point you need to have grubbed together every possible orb and dark bone and potion reagent to be at the correct place on the game's curve to win. It's rough, given how random things like orb drops are. The boss design also gets kinda... Fate Grand Order. Three turn warmup on aoe party nukes. Unremovable status effects with a Tolstoy novel worth of text. Surprise mechanics with slightly buggy code that make it impossible to use your deck (if you get the "class cards cost +1 AP and basic cards cost -1 AP" and you've removed all basics from your decks, you just lose.) And the enemy starts pulling high enough damage numbers that, if the rng focuses down Ishana, she just dies. Darkest Dungeon works because your characters are disposable and your runs don't need to succeed every time. It sucks in DD when you lose three guys to spider crits during a random ambush, but it's more tolerable than here, and that feels wildly damning to say. The longer the game runs, the more its shaky design is at risk of shambling apart.
2nd Edit: "You can't play cards of X color, duration battle" status effects shouldn't exist. Straight up, emerald does not have damage cards. So if you get the ol' no sapphire, no ruby special, either you have scapegoats stockpiled or you reset the run. The difficulty, length of runs, and ability for the rng to just unilaterally torpedo you increase wildly in the late game, and this is enough of a problem that it's starting to overshadow the voice acting.
3rd Edit: Cannot stress enough how much every character in the campaign is just lying to you all of the time about absolutely everything. And they're all different lies, so every time someone says something outside your worldview you think "ah ha! the truth!" but actually no you're still stuck in plato's cave. This means you can't really make choices, you're just kinda picking whose lies sound better to you, because it is not possible to even start to guess the truth of the story from anything you've seen. And they're not really lies you can test, it's all stuff about the intrinsic nature of the universe. And a bunch of the supporting characters are also actively lying to each other, so sometimes what you're seeing is a distortion of a distortion of a distortion that a character doesn't believe but they're trying to make you believe. And you don't have anything solid to compare it against, so like, sure maybe this was all caused by a god divorce. No way to tell, though, and you have to kill or spare someone based on whether you think this god divorce they just made up is real. Also they're going to do a ritual afterwards. What's the ritual for? It's a secret. It's interesting to write a story this way, but I think it's less interesting in an interactive medium with branched endings because you're just bouncing from lie to lie randomly like a pachinko ball. You're not actually making meaningful choices because it's impossible for you to understand the choices you're making because you are fully enclosed in misdirection, and this isn't a mystery story where you're supposed to figure it out. You're supposed to just get spun around and blind man's bluff your way into a random endgame.
4th Edit: Sometimes you don't receive talent points for completing missions. I'm pretty sure this is a bug. Either that or the talent point award formula is completely opaque. Also in the Maybe A Bug category, sometimes Hatred doesn't work. I'm assuming this has to do with triggers, but I've cast a big expensive card and had it not double. Also, are there caps on some buffs? It seems like there are, but buffs don't explain if this is the case, nor what the caps are. Also, when you're picking options for an event and it says "may start a battle or give a debuff..." but then you pick it and it awards you a reagent instead, what the hell. Slay The Spire works because you have information about your choices. If the mechanical outcomes you're choosing between are obscured AND they determine your progression (via orb and bone drops) and they're nearly 100% random, the game is deciding whether you can clear it or not. That sucks. You can play perfectly with your available information and still end up in a dead save if the rng screws you consistently enough and you don't realize you should be savescumming levels.
5th Edit: Other bugs. Choosing not to cleanse myself in the pyre caused dialog advancement to break, forcing me to skip dialog to get out of it. Which, like, thanks for that. The plot's extra hard to figure out when there's chunks you can't read. Also, challenges seem to have broken completely. I got one, after Naraka, and I'm in the endgame and haven't seen another since. Also I've invested in like two trap evasion chance upgrades and now my chance to evade is higher without tools than with tools.
