Ideology had added so much to this game and was really worth it due to all the fun and incredible additions that it not only helps make your colony truly unique and yours, but, has instantly added more creativity for the modders out there adding bits missing or not thought of by others and the creators.

Showing and demonstrating Ideology, plus additions from mods: https://youtu.be/FQ06v7SHVbI

Ideology adds a belief/political system to the game that you can use to reinforce faith and even create ways to make your playthrough more or less difficult, without either adding over-powered monsters and groups, making you an enemy to all or have your raid rating and frequency increased. It's a different and more fair kind of self-imposed difficulty through the use of what they call "memes" and "precepts" to make a truly custom ideology that governs your people and even having a fluid one that evolves and changes over time.

For an example, here are a few:

Animal personhood: Animals have rights as humans do. (No eating meat, but boosts to animal taming and harvesting too)

Tunneler: Humans ought to live underground, and enjoy the succulent fruit of the depths. (You gain benefits from living under the mountains and eating mushrooms, but negatives from being out on the surface like the views of dwarves in many fantasy stories)

Tree connection: Trees are the essence of life, and we must be near them. (Bonuses to farming and such, though negative to cutting trees and using wood to build is far easier than harvesting, making and building stone structures)

Cannibal: We must consume human flesh. (Like I reverse of the animal personhood, but often, your colonists get upset is they eat even one meal that doesn't contain any human meat in it. EVERY meal must have long pork on it!)

Transhumanist: Human progress means merging with technology. (For those who want to go full bionic, get boosts to research and unique buildings to reverse and enhance colonists)

Flesh purity: The human body should not be debased. (Kind of the opposite of Transhumanism. Loving pure human bodies but hating any kind of prosthetic)

Raider: The strong should take from the weak. (It's required that you commit raids)

Proselytizer: It is our duty to spread our beliefs. (You can passively change someone's ideology without having to arrest them)

High life: Exotic states of mind are central to a good life. (For all of your stoners, maaaaaaaaaan)

Supremacist: Our people should dominate all others. (We are the one true race!)

Loyalist: We stand for our own before others. (For those who don't want to go as far as supremacy, but still focus on the idea that your colony is the one true colony)

There are so many more that I can't cover here without making this review far too long, not to mention the many more that have been added with mods and the later DLC, Biotech.

Precepts are more flexible rules, allowing things like cannibalism, insectoid meat and such to be liked or hated, but at a lower priority instead. Again, huge amount of extras given through the modding community that I'm not certain I am accurate in separating what ones are vanilla or not.

Another major improvement is ofcourse, the Garulian Tree. Much like the anima tree in the previous DLC, this one is a unique tree with it's own abilities, however, it's a tree that you can psychically link your colonists to and in return for clipping and maintaining the tree a couple of hours every day, it produces small creatures and grows bigger in size. These creatures are called dryads and they can be shaped into different types that have all kinds of uses.

Some can be warrior castes, haulers or produce resources passivly like wood, berries and even seeds for even more trees to spread all over the map and allow for more colonists to get bound to these trees as each tree has a limit of colonists to mentally link to and the cap never rises, so it's best to get more trees.

On the surface the mod seems pretty simple, but allowing so much choice allows you to have fun with all kinds of colonies that you can make. A group of cannibalistic nazis or maybe cyberpunk nudist tree lovers or hell, in my case, I made a group which ends up with a very rude shortening: https://youtu.be/_uDXMe-jQKY

As you can see, lots of fun can be achieved with this and it's totally worth the price to add to the main game!