Spells (Specific)
Ignite: It feels terrible to use. I know it isn’t strictly bad since it’s a highly mana efficient damage source, and you can use it on an allied fire elemental, fire mote, or yourself at 0WP to mitigate most of the downsides, but maybe increasing the mana cost a bit and causing Ignite to grant a significant increase to fire resistance (such as 50 to 100) for its duration would make it feel less situational.
Earth kick: I love the idea, but I found actually using this skill to be extremely difficult. This time, I have no suggestions on how to change this to make it feel better to use.
Volcanism: The limited area of enhancement just isn’t satisfying to me. Maybe increasing the enchanted area, or creating an upcasted version which enchants all summoned rocks regardless of range, could make this ability feel better to use.
Leather spell tree: I use the leather skill tree a lot because it offers a utility (Silence, blind, disarm, snare, rapid fire). However, there isn’t a single spell cast verbally or with legs, which can make it feel like a one-trick tree at times.
Elastic grip: It would be pretty cool if you could also target a wall or immobile object with this ability, and be dragged 4 tiles closer to the target.
Blessing of Obscurity: Maybe a passive could be added to the Blessing of Obscurity which increases stealth or critical damage, since right now this spell tree feels a little lacking.
Restraints (General)
Rare Restraints: With the addition of the Summit and NPC binding, it would be nice to have ways to obtain currently inaccessable restraints such as shadow hands and the ice series, as well as new ways to obtain restraints which are currently quite rare, such as the holy rope series (though I suspect the corruption/divinity update will make this specific set less rare), or the Ectoplasmic series.
Reject metal, return to rope: Currently rope-based bindings feel weaker than other types. Perhaps a higher-grade variant of the holy rope series (angel’s hair rope?) could be introduced to reduce the power gap between ropes and other restraints. Since more bosses are planned for the future, maybe a pitcher-plant type boss (Nepenthes would go hard as a boss's name) or semi-boss (like dragon queens) could be introduced to add new vine restraints and a unique encasement.
Other
Meta-progression: I brought this up in the Perks (General) section, but implementing mechanics to give progression between runs instead of just within a run could make the game feel more polished, and could make it more replayable. A lore-based progression of this type already exists in the form of collectable journal entries. Perhaps allowing players to choose one weapon or restraint to take with them into their next run, or creating a kind of hub area where you can use some kind of currency accumulated from previous runs (such as gold, or some 'score' based on how many floors you cleared, enemies defeated, and similar) to purchase upgrades for subsequent runs. I think something of this nature would enhance the roguelike appeal of the game.
In-game explanations: Despite having played for a long time and reading the patch notes where I can, I still have little to no understanding of several mechanics, even mechanics which have existed for a long time. An in-game encyclopaedia with information on everything you have encountered would help a lot.
For example, having a brief entry on every enemy you have defeated at least once before, every item, weapon, and restraint you have collected at least once before (even if it just an index of the existing descriptions), as well as tiles/map features of interest (such as bondage machines, cracked walls, hooks, cages, spell orbs, different chest types and such), and status effects (blind, conductive, edged, and such). An in-game resource explaining these features will make the game MUCH more approachable for new players, and easier to understand for more experienced players.
It can also serve as a checklist - for example, I have never been certain if weapons such as the Moirai's Scissors (alongside Metamorphosis, Four Seasons, Dragonslaver and such) are actually obtainable, or if they are exclusive to debug mode because no method to obtain them has been implemented. Maybe each one is attached to reaching 100 reputation with a certain faction and I've just never done that, maybe they simply can't be obtained legitimately, maybe there's something I'm missing - but in any case, I have no way of knowing or even guessing using the tools provided by the game itself.
OP loot and single run progression: I think purple chests are too strong right now. The first time I managed to beat the Dollmaker was several updates ago, and at that time, I was getting hard-carried by a pike with a good enchantment. Purple chests give extremely early access to powerful weapons such as the staff of storms/frostbite/incineration, or the Shadow's Edge, which make most non-boss combat trivial.
By the time I reach the Warden, I typically have all 3 elemental staves, and some combination of other rare and powerful weapons. While these weapons did exist in the past, often I found myself with only 1-2 of them by the time I reached Floor 20. These powerful weapons are actually more common than their weaker counterparts (Staff of shocking/permafrost/flame).
In other words, you get extremely powerful very quickly, then nothing better for the remainder of the run. This is notably less obvious if you use a spell-heavy playstyle, since MP and skill orbs are more limiting than weapons.
One method of dealing with this could be by adding a weapon upgrading or enchanting system (possibly tying in with the Summit's functionalities?). One possible implementation of this would be obtaining a staff of shocking from a purple chest, then requiring an ally from the Nevermere Trainers faction to have an opinion value of over 50 in the Summit, and requiring some amount of resources from recycling bondage items to upgrade the staff of shocking into the staff of storms.
Bug with conduct: The damage from conduct is sometimes not properly rounded, with the damage received from conduct being reported in the log as follows: “0.9750000000000001 electric damage conducts to you!!!” (12 zeros)
Closing Thoughts
I really like this game. I want to see it completed, and in the best state it can possibly be. The things I've mentioned above are that which immediately stand out to me as points of improvement, both minor and major in nature. I really hope Ada reads this far and takes an interest in at least some of these suggestions. I'm a little worried about feature-creep, but I'm also interested and excited for what future updates hold. I've been waiting for a long time, and I'll keep waiting as long as it takes, so do your thing Ada, and make this game the best you can.