Became aware of this from your post on 4chan looking for feedback. I just played through the first five dungeons (on 0.6), and wound up writing more than would fit there, so posting here instead.
Starting with mechanical notes...
I didn't figure out that healing items were reusable until the second dungeon; it would've saved me some time if that'd been made more clear. That said, especially in later dungeons, I often found myself wishing there was a revive item; sometimes enemies randomly focus down one of your characters quickly, and it's annoying having to reset despite having plenty of other healing items because there's no other way to get them back up.
Generally, it felt like there weren't enough healing items to casually clear floors, so it was always important to be strategic about which fights I took. At the same time, though, that lack of healing items inspired me to completionist exploration; I wanted to be very careful to check everywhere for chests to make sure that I wasn't missing any healing items. This was more irritating on the more confusing dungeons; worst offender was the mummification dungeon, whose 3D maze layout made it a lot harder to figure out where I'd finished checking and where I still needed to go.
Debuff effects often felt a lot stronger than buff effects. Mami's Ribbon Tie made such an amazing combination with Madoka's Lovely Barrage that I rearranged the party to put them in first and second, which remained a great opener against large enemy groups until the hardier enemies in the fifth dungeon became tough enough to ignore most of that damage. Similarly, in boss fights, it almost always seemed like the right call to debuff a boss instead of buffing one character, since the boss would be doing its thing every turn, and messing with its ability to do that was always fantastic. It helped that later debuffs often combined with attacks, so it didn't even feel like I was wasting a turn to put the debuff down.
Unfortunately, many buffs often felt questionably-useful. I eventually found Parry Stance necessary in the fifth dungeon, to enable attack-focused characters with attack debuffs to contribute much at all, but it wasn't exciting; I'd hoped for counterattacks when I read the name, and was disappointed when that wasn't the case. Guardian Stance was a big enough swing that I did wind up using it often, especially since my Sayaka lagged far behind the party on offensive moves; the fact that it applied such a big buff to the target without stacking its debuff on Sayaka made it feel worth her time. The idea of Madoka's Glitterdust was neat, being a unique effect instead of another stat mod, but in practice it often felt like I'd rather do something else, and I eventually traded it out. I was quite happy with Kyouko's Spearchain in most circumstances, combining decent damage with a decent defensive buff always felt like a reasonable move. I would've liked to see more buff combos like that, or AoE buffs.
As a map explorer, I was generally disappointed by the lack of equipment, up until the Cursed Loot dungeon. Then I was disappointed again by the way you didn't get to take any of the good stuff with you afterwards.
Mechanics aside, talking about fetish content...
Enemy art was generally uninspiring. This is an HRPG, adding naughty enemy sprites would go a long way towards selling the mood.
The first dungeon was mostly kinda boring. The characters got stripped naked pretty quickly... and that was basically it, aside from the grovelling from the boss's attack. Unless something is going to take advantage of their nudity, being mostly naked is actually more interesting than being completely naked. Instead of the bulky and boring rags, I'd have liked to see an item that restored just their underwear, since seeing them desperately try to preserve the last shreds of their modesty would've been more interesting than them just being totally naked with no way to solve it.
The second dungeon was much better supported, with the many items in the first room to apply or remove the corsets and heels. Instead of just having them quickly forced into the highest heels and tightest corsets, I'd actively cut away any items that were too debilitating, and instead try to keep everyone wearing gear that they were just slightly uncomfortable with to maximize both training and combat power. It was a neat concept, and didn't wear out its welcome, since the enemies were effectively helpless against fully-trained characters.
As a cursed item enjoyer, the third dungeon was incredibly disappointing. There could've been a lot more done with the items in question (see literally any of /d/'s cursed item threads for ideas), and instead it was just minor stat debuffs. Combine this with not even being able to keep any of the actually-good equipment for later, and I wound up not enjoying this one as much as I thought I would. That said, I see you're already on this one and going in a petplay-focused direction; I look forward to seeing what comes of that.
The fourth dungeon was mostly just a long boring slog. Without any other interesting things happening to the characters when they're wrapped up, it was just... kinda silly? The bondage sarcophagus move used by the final boss was a little neat, but mostly this place involved wandering around a maze searching it for loot while heavily debuffed. The lack of interesting ways to respond to the progressing mummification other than collect the items that let you opt out of it, and general lack of things that exploit your bound state made this easily my least favorite dungeon.
The fifth dungeon had some neat concepts, but felt underdeveloped. Sure, I managed to find the stuff to shrink futa cocks and break out of chastity early on, but the debuffs didn't feel significant enough to force me to use it, and the training duration to get the titles was long enough that by the time I was ready to consider breaking out, I was basically just stalling before the boss fight. Worse consequences for being maximum horny and unable to masturbate while having the biggest dick crammed into the tiniest cage would've sold this harder. I also would've appreciated larger / growing plugs and an anal training progression instead of just waiting for a long time while plugged; 1000 steps was so much that I wound up walking back and forth in a long hallway for a while to get it done.
I didn't play the sixth dungeon, since it was the last dungeon when I played, and feeding and weight gain isn't my thing (even if the weight is only going to tits and ass).
Generally, I was a little disappointed at the lack of lasting fetish-related consequences to the dungeons besides the titles. For example, it'd be amazing if completing training in corsets and heels unlocked alternative outfits that, or if some piercings from the cursed dungeon could be worn afterwards (either case probably being sidegrades instead of upgrades, allowing more customization of the party). That said, I understand that there's only so much art you can make, and there are possible inclusions that'd make later expansions more complicated.