Rimworld

• Nice background music
• Loads of content and events
• Lots of difficulty settings
• Mod support, with a large modding community
• Useful settings for cooking meals like "until you have 5" rather than manually always adding recipes (like ONI)
• Extremely granular rules, if you want, for all kinds of things. There are settings for work schedule, what food people are allowed to eat, what medicine they're allowed, where they can go, which animals are allowed where etc. This is awesome, but can also cause a lot of confusion; like trying to find out why my colonists wouldn't store herbal medicine anywhere. The storage allowed herbal medicine, but turned out it didn't allow "fresh" items.
• You can also set policies for what kind of clothing people are allowed to wear (and set roles for people). It took me a LONG time to realise that. One of my colonists was permanently grumpy because he was wearing a tattered hat. Turns out you have to edit the clothing rules to only allow items with more than 50% hp remaining, otherwise he'll conitnue to complain and wear something that makes him unhappy.
• You can domesticate animals and farm them for produce, meat, leather etc.
• The game is an incredibly detailed simulation. There's so much to mention here. Colonists have individual body parts. The world and the rooms you build have temperature with themodynamics and insulation. There's a roofing mechanic. There are raids. Combat. Colonoists have relationships with each other and get depressed. They have personality quirks. You can capture raiders and take them prisoner, then sell them as slaves or recruit them. The list goes on.
• Animals will breed. You can create an 'auto-slaughter' policy for animals so you can automatically keep your herd sizes down based on the animal growth stage and gender
• When you create your game, you choose where in the world to start. This affects everything on the map you build your colony in, such as growing season, average temperature, land features (hills, mountains, river etc)
• Everything you make from walls to furniture to clothes, can be made out of different materials. The clothes you make have different properties such as thermal insulation and protection depending on the material you make them out of.
• Your colonists and animals generate dirt which needs to be cleaned. The cleanliness score of a room doesn't only affect happiness, but also things like medical procedure success chance

Despite any and all of the below, I either found ways around them, learned what I needed to, or found a mod for it.

• Ugly (but you get used to it). Subjective, but this was what put me off the game for years
• Steel is a flammable material
• No Steam achievements
• The UI is really unintuitive. Even after playing for 4 hours I'm never sure where to look for things. There are lots of oddities that can be confusing until you Google them. For example, at one stage I could only make things out of steel instead of wood like I'd been doing so far. Turns out there's a tiny arrow next to the item menu that lets you change the material, and I'd run out of wood
• Without a mod, there's no way to get the camera to follow a colonist to see what they do
• It took me a good 10 hours to work out how to improve "room score" (it's a combination of wealth, size, decor, cleanliness)
• The artwork for the colonists walking around your base does not include arms, hands, legs or feet. The system behind them is very intelligent, but the graphical representation means that you can think they're fine, then realise after a few hours that they're missing an arm and need a prosthetic
• The modding community is huge, and that's good because the base game does some basic things really badly. The trade interface is confusing. Colonists will walk into their own traps. Colonists will use super medicine to treat a bruise. Colonists will collect fertilised eggs and eat them when you want to hatch them.
• Rooms are auto-tagged based on what the game thinks they're for. That's fine, but an unexplained mechanic that caused an issue I only found the cause of after a few hours. In my "kitchen, recreation and dining room", colonists were ignoring the table, walking out of the room, outside, into the prisoner room and eating at the table there, because the area I had designed was only tagged as a kitchen.