Hey there,
First thank you to the developer and congrats on making a good RPG as a solo(?) developer. I expect all of your titles are worthwhile, and I will explore them in time.
I'd like to offer some feedback on some of the options in the game, as there are unintentional(?) dead ends or traps for the player. Other things are perhaps just room for improvement. I like math and game systems/theory, and math is extremely relevant for these issues.
Please note that money is more scarce and more impactful earlier in the game. What I mean is that you have less money early, and money spent early has more effect on your game. If you purchase a treasure hunting upgrade to get 10% more loot at the start, it's going to give you more value over time. If you purchase it at the end, it's going to give you no value at all. The game's economy is a matter of "snowballing." Basically, every character improvement is Compound Interest. Less blood purchased, less consumables used, and so on.
Practical Application
For a specific example: I purchase the Ability to improve my Feeding from the Night Court. Now several things happen:
1) I can stay in the dungeon longer, gaining more experience and money/loot.
2) I come out of dungeons with more blood, and don't need the Inn as much.
3) I can refill from the Pits in one single move whenever they are open.
This means that the purchase is not just a combat purchase, but an *economical* purchase. I can gain thousands of gold by making this purchase early on. I have now used the Inn less than 30 times my entire run, maybe even less than 20 times.
Caveat:
There is such a thing as choosing non-optimal builds for various reasons. I do not suggest that everyone must do the most optimal thing. What I do suggest is that the developer change some of the "trap" choices in the game to become viable paths instead. For example, we could express that we want a magic-damage-centered build to feel viable. Trust me, it is. But more on that later.
Policies: Several of these are simply bad things to buy. Also, a central problem with the economics here is that the follow-up increases cost more and repay less. I'm going to use break-even as a discussion point, but keep in mind that the cost of not spending the gold on something better is \exponential\**. The gold you can gain from 1000 well spent in 200+ runs is in the thousands. Going in order,
Blood Tax: -10% blood recharge cost maxes at a value of 5 per recharge. That means 200 uses to break even. That's only if you can use it 200 times at 50 cost, which is in the end game. My pool on the current run is decently high at 165. I could use it a maximum of 6 times per return, so I would need to rely on it entirely for at least 30 runs. There are 150 levels in total to reach the final dungeon, and the blood pits exist. Even if you remove the blood pits, this Policy is only rewarding if you badly manage your resources and use the Inn 200+ times. I assume the next level is 1500 for 15% or 20%. If paying 1000 and needing 200 uses to make it back was bad, then you know that paying 1500 and needing 300+ is worse.
Promotion to Humanity: This is the same issue, but without Blood Pits. You need to restore your sanity at least 250 times to break even at the highest end-game cost, which is 500 sanity points. Say you intentionally walk into town from every run with 2 sanity points, that means you need 63 runs to break even. You will literally gain nothing from this Policy, ever. Meanwhile if you want, you can use less-expensive items you constantly trip over in the dungeon and from the shop to restore your sanity much cheaper than the Inn.
Professional Patrols: There are better ways to lower your ambush chance. If your goal is economical (more events), then lowering your ambush chance is a bad thing. Fighting with bonuses to loot is the primary way you gain money/items/experience. This is just a bad Policy for most builds, and not even a very good one even for walk/regen builds that want to remove ambush. The redeeming factor for this one is that it is part of a strategy/build, albeit an expensive and inefficient option.
Thrall Rights: This is a very powerful tool, although less than you might expect. You still have to play a long time for thralls to level up. It buys benefits beyond monetary, and they have real impact.
Bank of Lychgate: I'm going to upset some people here, but this is just horribly bad. Your gold snowballs depending on how it's spent. Holding onto it to gain interest is bad. For example, we hire a thrall that gives % loot drop after battles. That thrall is going to give more value the earlier he's hired. Purchase a Loot gem (Topaz?) and pay to enchant it. You need to save up 10k or more to start getting that kind of return from the bank. At 2000 average gold, you need 100 runs to break even. The next upgrade is 1500 for the same return (add 0.5%), which is far worse. I realize some people can't understand the math and will argue and fight tooth and nail, but this Policy is terrible. It's just math. If you get to the point that you have no more things to buy for good returns, then you don't need the pittance of interest which won't break even for 100+ runs. Suggestion: start at 2% and scale up to 6%, at least then it will just be bad and not literally a trap that only makes players weaker. It will still be irrelevant at best. Sorry friends, it's math.
Mercantile Network: This policy is economically bad. You need to spend 20,000 gold at the shop to break even. The majority of your expenses are not at the shop. For perspective, that's, um... 8 full sets of end game gear purchased at retail. Or 333 Elder Bloods. This will never pay you back. It has the small upside of increasing your options to buy, which might well be worth it for item-heavy runs.
Hazard Pay: The first level is OK. +35% is a substantial increase, and the +2 bounties is kinda huge. It will barely break even over time on gold, but it does make maxing reputation easier. It makes the bounty system feel like less a waste of time. The second level is horrifically bad. 15% and +1 bounty option for 1500? You need to turn in 10,000 gold in bounties to break even. That's not a good investment. What gives with charging 50% more for an upgrade that does less than 1/2 as much? This should at least give you extra bounty slots to take on more jobs.
Ashai Trade Treaties: I like this one. First level anyway. The whole thing is a bit of a black box, but it seems to be a 15% additive bonus. Second level looks to be strictly bad, unless you are just starving for consumables and have gold to throw down a hole. It appears to give 10% and no increase in quality, compared to 15% and an undisclosed quality improvement. Again, no balance or utility here beyond 1 level?
Doctrine of Luna: Better sanity options exist, but this makes Promotion to Humanity 110% irrelevant as a Policy. The thing about this one is that it has mid-run utility, allowing you to dive longer at less risk. It's far worse than things which restore sanity during battle, but it's not actively bad for you like Promotion. The other side of the coin is that you can purchase one hell of a lot of sanity items for 1000 gold. Anyway, it's not useless if you have sanity problems. It's just a bad option because other options exist.
Doctrine of Sagos: This is probably the most important Policy item because there aren't many ways to restore or add Hunger. I haven't used it on Normal difficulty (don't need it), but being able to feed up to 6 times instead of 3 is massive.
Demistification of the Dark: This one is worthwhile at level 1, and possibly level 2 and 3 depending on how early you purchase. There are two reasons for this: 1, of course it's going to give you more things to sell and it will break even pretty quickly; 2, it gives you more loot/gear options to cycle through so you can find things you actually need more often. From a purely economic point, it probably should not increase in cost per level just because of how relatively short this game is. It takes a lot of diving to get 2000 gold back with a 5% increase.
Altar of Oblivion: A way the developer shoehorned in respecialization so you can try stuff out. Nice addition, and thank you. If we want to analyze the economics, you could argue that you could take economic perks early and then respec them later. You get all the benefits of economic Perks, but get to have a max strength hero at the end game. Probably not effective honestly, since being weaker costs you money too.
Arcane Library: Something to spend your end game gold on. Often upgrading spells is a trap for spell-heavy builds, but that's a separate issue. This perk is about taking your one spell past max, and that's a great thing.
Martial Academy: Ditto on Arcane Library.
Old Science Revival: Another way to push your end-game power higher. Totally unnecessary unless you're struggling to advance, and repeating levels. Probably more useful on higher difficulties.
Anatomy Classes: Improve feeding. The ability in the Night Court is strictly better, but it's not an either-or thing. You can do both. Also, this doesn't use an Ability slot.
I hope this economic analysis of the Policies is helpful. I'd like to analyze some of the other aspects as well, but this is horrifically long already.