Note: This post is quite detailed. If you want absolutely 0 spoilers, don't read it. Not story spoilers, but game mechanic spoilers.
there are some key differences to KODP, which change the play style of six ages a lot. I won't spoil the story though, that is for you to find out.
Many kodp features such as giving gifts, holding fiests etc have now been moved to ventures. These are undertakings your clan can attempt, you can do one each year, but you may be able to do more later. These ventures can range from hunting for extra food, to trading with your neighbors, to searching your lands for bandits, with different benefits if you succeed.
Horses play a larger role than they used to. Since your clan is part of the people called riders, every child learns how to ride, and everyone fights while mounted. This means you'll have to keep a closer eye on your horse population and you'll also have more of them.
Combat is a lot more interesting here, as you have a lot more control on what your forces attempt to do. When combat starts, you can choose from several initial actions, such as conducting a magic ritual, creating a reserve force or maneuvering for a better position. While fighting, it plays much like a rock paper scissors on steroids. You can choose how you fight in the current round, and it will be pitted against your enemy's choice plus a lot of factors like active blessings, number of warriors etc. Of course there are mid combat heroic scenes that can change the battle's outcome as with the previous game.
Magic: The god mechanic is something you should be familiar with from kodp, as you can still sacrifice, build, and do rituals. However, a major new element has been introduced, called spirits. They are lesser enteties you can buy or capture, and they can provide a blessing to your clan if you bargain with it, though might not always grant it.
Exploration: Some great improvements here. Instead of selecting a hex and sending your party out, you will now be shown a list of locations you've found where you can go, as well as unexplored places. Your exploration party is able to do a lot more than simply look for undiscovered treasures, they can also try to capture horses, forage, or find spirits.
Relations: Unlike kodp, you're given a lot more info about how people are disposed towards you. There are two scales that matter most. One is how well they like you. A clan can hate or like you, or simply be neutral. There also is a respect scale, so a clan can fear you on one hand, and mock you on the other. Because these two are separate, any of these states may occur, so a clan can e.g. hate and mock you, or they can like you but also respect your might.
Accessibility: They've definitely done a lot of work here too. Most things have vo hints now, so it's a good thing to have them enabled. You can for example go to any clan name on any screen, and the hint will tell you things such as it's chief, their relation to you and other stuff. Many scenes in the game that have artwork now have an alt description that describes what can be seen.
Concerns: These allow you to keep track of what's happened so far, and they can be quite helpful. They can be anything you should be immediately worried about or you should take an advantage of, such as an omen that gives you luck when raiding, damaged pastures, or having no instated chief, which hurts your magic.
Bar, bar, bar...
Bar is my name and to go bar is my aim...
Sometimes I'll go "Bad bar",
But in the end its always bar, ahem beer, ahem bar! beer bar!