It's honestly wrong that the game has mixed reviews. As someone who enjoys JRPGs with deep gameplay mechanics such as SaGa, this game immediately hooked me. It's top down, tile-based, turn-based like other mystery dungeon games, where every action, even moving 1 tile, is a turn. Positioning is important, there are many effects that affect positioning, the game rewards thinking about your every action, yet the pacing of the gameplay is fast. There are boss fights that challenge you in every way you can expect: learning boss patterns, making appropriate preparations and improvising in the moment. You also first need to get through the dungeon to reach the boss and dying would send you back, so the stakes are high and winning feels very rewarding.
One of the things that make the game stand out is the crafting: you can craft weapons any time, anywhere. You can use the scrap of your previous weapon to carry over what you had into a new weapon. You can gradually build towards stronger and stronger weapons. You can make weapons for different situations. The further you get, the better the materials. There are over 100 weapons. Depending on the materials, you can create different ones, so you constantly keep finding something new. Combined with additional effects you can add, the possibilities are endless and you can create various builds that feel completely different from each other.
I could talk about the gameplay all day with how much depth it has, but as for other aspects, I'd say the story is decent, dialog is decently entertaining and fully voice acted in Japanese, music is mostly royalty free but it fits and there's variety. Visuals are really good, especially the bosses look very impressive and menacing, and there's some really nice art in cutscenes. There are some quests and hand-designed dungeons. Overall it took me about 70h to beat on hardest difficulty, and aside from a few cases, I was always making progress and seeing new content. There's also post-game.
I went back to play the original Shiren The Wanderer to get an understanding of the roots of the mystery dungeon genre, and wow, it's cool what Shiren did back at the time, but also this is a huge evolution of that. I'll have to try some other mystery dungeon games, but man it's hard to imagine anything topping this gameplay-wise for me.
Also, let me address what some might be wondering: yes, it's an Eroge, except the Steam version is censored and completely omits such scenes. And yes, there's a patch to add them in. There's some lore in some of them but nothing important.