It's unfortunate that the best hentai in this game is locked behind the death routes, I just can't really get into that.
Its a depressing environment for sure, but its pretty much an alternative dungeon without any save-points. From a gameplay loop perspective, its pretty innovative (or at least, very retro / inspired from games a long time ago). Looking at guides, it seems like there's 21 floors. And since the characters stats are so low, you have to plan the use of every item and plan exactly every combat if you want any hope of actually reaching there.
Its not my kind of game. Its... kind of like a turn-based Tower of Druaga where no matter what you lose at the end (IE: Woops, that item on the 3rd floor was needed to get past the 6th floor. If you didn't get it, you lose. No save, start back from the beginning). An old school puzzle, they don't make games like this today. And yet... it makes sense as a "mini-game / extra dungeon" that exists only in the 'bad ending' of this game.
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The main game, at least the first couple of chapters, is pretty easy. But with absurdly difficult extra bosses littered around. RPGs can be self-balancing like that: a casual player can skip the strong bosses, while a "hardcore" RPG player can try to defeat them.
Overall, I think its a well designed RPG. Albeit with some ancient "Nintendo-hard tropes" in the "locked bad end" that I haven't seen in decades. The hard bits are always optional. The mainline story is good enough and there for the writing, clearly.
This is definitely a "buy for the game" rather thn the H / Ero.