In a nutshell, Cult of the lamb is a game about a lamb who leads a cult in the name of a bishop called The One Who Waits. The game is kinda of a mix between animal crossing and the binding of Isaac but if animal crossing had murder and if the binding of Isaac was... well, the binding of Isaac but less punishing.

The game begins with you playing as the lamb, tied up and only able to walk slowly, the lamb walks towards a sacrificial altar surrounded by hooded individuals and 4 tall beings. In here we are told that we are the last of our species and with our sacrifice some prophecy would be imposible to be realised preserving a cult called the old faith. So our head gets chopped off and the credits roll.
Ofcourse that doesn't happend, instead we wake in a white place where we meet a bishop called The one who waits. He tells us that our sacrifice in the end was in vain for the 4 bishops since our death was an attempt to keep us away from the one who waits. He tell us that he will bring the lamb back from the dead but in one condition, to stat a cult in his name. The game then gives the player the ilusion of choice and we can choose between yes and absolutely. Anyways The one who waits gives his crown to us, revives us at the sacrificial altar and with the power of the crown we beat up some heretics. On our crusade we meet a rat named Ratau, in his words, a once chosen vessel like the lamb now sent to guide us to become a cult leader, basicaly Ratau is the tutorial of the game.

There are 2 main things you will be doing in cult of the lamb: Taking care of your cult, going on a crusade against the old faith or if you are a gambling addict gambling your money with Ratau at his house.

Taking care of your cult is not only essencial to make progress in the game but its a way to make you stronger for when you go on a crusade. ofcourse a cult is nothing without their cult members, when indoctrinating new cult members you can see their traits, you can customize their form and whats most important IMO giving them names. Giving individual names to all the cult members makes each one of them memorable in a way, and kinda build like an emotional conexion between you and your cult members, like for example beign on a crusade then a you see a pop up that says "Pedro porro is starving and will die if he doesn't eat" and you have to cut short the crusade to go back to your cult to make food for Pedro porro because you dont want him to die, or feeling bad for sacrificing Pedro porro to get a steam achivement. And i like that, i like when games makes me feel diffetent emotions.
Anyways, cult members have their needs, just like any human being they eat, they use toilets, they sleep and they die. So you have to build houses, cook them food, clean their poop and also because this game is about cults you have to perform sermons so you members gain faith, in addition doing sermons gives you "sermon points" and when collecting enough sermon points you are able to upgrade the lamb in a skill tree system with abilities that helps you on your crusades. Another and faster way of getting "sermon points" is by sacrificing one of you cult members in a ritual.
Before going on a crusade it is recomended that your cult can keep themself alive for a day or two because you cult members will do their daily routines even when on a crusade, so if you haven't feed your cult and go on a crusade your cult will lose faith because you left them to starve. I heard from some people that they dont like the cult system because of that but its something that you only have to take care early in the early game.
another thing that you can do is blessing your cult members, doing this will allow your members to gain loyalty and when getting enough loyalty the member will level up and in return you get a piece of a commandment stone, get 3 and you can now establish a doctrine in your cult and ohhh boy some of these are a bit busted. When choosing a doctrine the game gives you 2 options, for example one of the first choices you have is between the ability to murder your cult members or unlocking a ritual that lets you choose a cult member to "ascend"
lets say you pick the ability to murder your followers, now you wont be able to use the ascend ritual for the rest of the game and stuck with the ability to murder might as well test it, lets just hope we dont come across into a guy in a chicken mask talking about hurting other people.

To beat the game you must kill each member of the of the Old Faith, each one of them located in diferent places, so the Lamb must go there and commit several crusades by killing their cult members and local wild life, with the help of the crown that can turn into any weapon with the exception that each run gets you a randomized weapon, you can get swords, axes, daggers, gauntlets, hammers, and as of writting they revealed that they will be adding a gun for the next update of the game so thats cool. On top of the weapons the Lamb can use curses to his advantage getting the ability to shoot fireballs, blast of heretics, spawning tentacles and many more. You can also upgrade curses and weapons using the levels given to you by the "sermon points".
Ofcourse we cant have a dungeon crawler without having unlocks that aids us on our crusades by giving us pasive abilities or active items, on our crusades we can find various types of NPCs that can unlock places for us to go, on these places we can find diferent quest and some of them rewards us with tarot card or relics. Tarot cards are your pasive items, on your crusades you can get cards from chest or from a guy called called Clauneck a tall red bird, when encountering Clauneck he lets you choose between 2 tarot cards, normaly these cards give you more hearts, multiply your damage or become invulnerable to certain effects. relics are your active items, you can get them from a blue wide looking bird called Chemach or from a random room reward. Relics need to be charged by dealing damage to enemies while some are one time use. Must say one of my favourite relics is the Aethrile's Powder Box, a relic that when used it will use a random relic effect and i wish for more wacky relics or tarot cards like the Aethrile's Powder Box to be added in the game.

So crusades. Crusades are divided in "sections" when beating a section you get to choose what section to go next but you must choose carefully, you cant go back to past sections blocking you off of certain routes. There are diferent types of sections: Your normal dungeon crawler where you kill heretics, areas where you collect resources for your cult, areas where you can get a tarot card or a relic, a shop where you buy stuff mostly for your cult, an area where you rescue a potential cult member from being sacrificed and many more.
The last section is a boss fight that after killing it will get you closer to your mission of killing one of the bishops. to get to a bishop you must first kill 4 bosses from its "biome", also since this game is a roguelite when you die you lose half of your resources and killing a boss is kinda like a save state so if you killed 2 bosses and died you dont have to do those bosses again.

Cult of the lamb isnt the best dungeon crawler neither the best civilization builder but i really like how well implemented both systems are.
The music this game has fits perfectly with the theme of cult of the lamb and composer River Boy did a great job with the music.
And you can tell that The developers behind cult of the lamb, Massive Monster, are taking care of the game with their free updates, for how active they are in the comunity and the many sneak peaks they post about future updates.
There is this video made by ThatGuyGlen that talks about how Cult of the lamb was made, so if your interested in that I recomend you to watch it it is a great watch.