This post was actually written a long while ago, the week the game released. It used to mention that if you buy the game now, you would get the so-called "perpetual edition", which gives you all DLC for free when they come out. The time has passed, as the article never got released on the website it was supposed to be on at the time, so I'm publishing it here instead. It was also supposed to be my first impression of the game, but I have since finished the game, so I expanded on some points compared to the original article.
Book of hours is a new game by Weather Factory, of the Cultist simulator fame, that came out in August of 2023. The game's steam page describes it as "an elegant, melancholy, combat-free crafting RPG set in an occult library, from the creator of Fallen London, Sunless Sea and the double BAFTA-nominated Cultist Simulator". Indeed, unlike their previous game, this one is much more relaxed and does not hurry you along all the time.
If you've played Cultist Simulator previously, you know how stressful that game can be, you always need money to continue paying the bills, and to get money you have to work various jobs almost non-stop, or sell things. Book of hours also features the mechanics of work and money, though this time it's not strictly required to keep playing. You don't need to pay the bills or get food or anything like that, you only spend money to pay people or buy things. Mostly pay people, as you'll be needing a lot of help with how the game's exploration mechanics work.
Unlike Cultist Simulator, you are no longer tied to just a table with cards on it. The game still features cards, and card slots, and aspects, all the same core mechanics, but now there is a map that you have to explore. You start the game washed up on the beach with nothing but a wet book. From there, the game expects you to figure things out yourself: there is no tutorial, no arrows, no message that helps you get started, besides a tip on how to navigate the map. Really, this is all you need to start out: look around the beach, try the different buttons you have available: the lock icon that shows where you can move to a different location (into the town near the beach) and the "consider" button.
Though the game features no tutorial or other help of that sort, many descriptions of cards, aspects, and actions now feature helpful snippets in square brackets that shed some light on the cryptic words in the box itself, and sometimes even tell you where this card can be used (however, this is usually not the only place it can be used in, just the most important one for someone who is just starting out).
Through various actions on the beach, you will get one of several starting parts of the soul that will define how your game starts and what mysteries you will be looking into first. As the game says, there will be more that you can discover later, but first you will need to get into town using some old acquaintance (which one depends on your chosen aspects), get that wet book dry again, and figure out how to get into the library, which you have come to the island to maintain.
As you've likely figured out from your travel from the beach into town, to unlock new locations you will likely need help of other people. It comes in many ways, both from town's inhabitants and the passers-through. Later, you will be able to also boost their abilities with your own, or various items. Unlocking the rest of the town shouldn't be much of an issue if you've gotten through the rest so far, talk with people, ask someone you already know to introduce you, that sort of thing.
From there, you should be able to ask someone from town to help you getting into the library, or as it's called in the game, "The Hush House". When you reach the first room of the house, you'll likely see that it's a huge castle with dozens of rooms that you will be unlocking throughout the game. The basic rule for unlocking them stays the same: you find someone to help you with aspects matching the room's, then you boost their aspects with your own parts of the soul, skills, items, or memories, by discussing these topics with them. Though be careful, as if you don't use their help by dawn, they will leave (as will the memories disappear). There are also a few rooms that are unlocked in a different way, but it's different for each of them and there are just a few.
In the rooms you unlock you will find uncatalogued books. This is the second major new mechanic of the game. You catalogue books, they contain a mystery of some level, you try to study them and match the level of the mystery with your own aspects, and if you are successful, you will learn a lesson from them, which can be made into a skill and put into a special tree that gives you more parts of the soul (this is how you unlock additional ones that you did not choose at the beginning). Skills always go into one of two slots in the tree, which gives you a lot of freedom on which skills you actually want to get. In the release version of the game, this caused issues where certain skill choices would lock you out from upgrading some parts of the soul, as the aspects wouldn't match the workbenches required for upgrades. This has since been patched, and I believe all skills are possible to upgrade just fine. Though there are actually less skills in the game than there are entries in the tree, so it is not possible to upgrade every part of the tree to the maximum.
With the books, the game actually introduces the two mechanics that will hamper your progress: infections and maladies. When you catalogue the book, the game will warn you of the chances the book may be infected: most of the starting books aren't, but there's always some small chance. If you get an infected book, read the description of the infection carefully, and you should be able to understand how it can be removed. If the description says the infection can spread, put the book in a room that doesn't have much of anything else - that way it shouldn't hurt you much. However, if you got unlucky and used the aspect of the soul that the infection can corrupt while cataloguing the book, it will become a malady; another way to get a malady is failing to study a book, so there is a chance the part of the soul you used will instead get corrupted the same way. It can be cured, as the description of the card says, and it cannot be used in many places, but there is also an upside to it: if you use it as effort in the things that allow it, it will not become tired, like normal soul parts.
As far as I know, trying to explore more rooms, catalogue books, and unlock more of the skill tree is the primary game loop. You don't actually need to explore the entire house to finish the game, but I have done so nonetheless, since it's such an interesting and huge place. There's also crafting, which you'll eventually need to create items to help exlore the house or solve mysteries in the books, and recently they've added a catalogue of things you have already crafted so you don't actually have to write it down manually. That said, it is still helpful to do so, as there is no way to see how to craft a specific item you need, just what can be crafted from the skill in the workbench. I highly recommend using some kind of note taking application or steam's built-in notes to write down your recipes, books and such.
It is very enjoyable to explore the game on your own and figure out its mysteries. If you're a fan of cultist simulator, you probably already bought it, and if you're one of the people who haven't played it: maybe you should try that one out too. It's a lot more punishing, but it has its own charm. If being constantly rushed by the game sounds like too much by you, the Book of Hours will definetely be more your speed. Both of the games make you figure things out and experiment in interesting ways. If that's something you're looking for, this is a great game, though the price of 22.49$ may be a bit of a turnoff for some, that price is well worth it.