Should I buy Dwarf Fortress?

As mentioned there is a steep learning curve, it is nothing like DRG.

There's a lot of different systems, and they can all interact in strange ways. For example: there was once a bug that caused cats to instantly die from alcohol poisoning.

If you like delving into that kind of detail in games, the steep learning curve, and the difficult gameplay. This is a nice summary:

The closest thing to Dwarf Fortress would be rim-world, the game is very complex but can lead to some very fun situations!

Honestly, once you get the basics down, it's really easy to survive if you make a fort in a place that's not close to anything dangerous. After that it's mostly about learning how to build various fancy contraptions like mist generators and traps and stuff. Then you can start trying to survive in more dangerous areas.

Also, how mouse heavy is it? I like to be able to do keyboard shortcuts whenever possible.

Mostly everything has a keyboard shortcut, in fact before the UI got overhauled for the steam release, there was only keyboard shortcuts, no mouse input was allowed.

It's a steep learning curve but it's really fun once you get the hang of it. I think the steam version is better in that regard. Also before the steam version the game was pretty much keyboard only.

Another thing: if you're on the fence, you can try out the entire game for free on the bay 12 games website, the only downside is that there are only ASCII graphics

The steam version tries to implement keyboard shortcuts as much as possible. Alot of 'buttons' will show the keyboard shortcuts when you hover over them. The ASCII version is keyboard shortcut heaven and hell.

There are so many interacting systems running under the hood that you won't be aware of (ie, the famous 'bug' that was killing cats). Play until one them kills you, then play again to see a different one kill you in an unexpected and fascinating way. Losing is fun.

They're currently working on getting the adventure mode implemented into the steam version that I'm really looking forward to.

The community is great and if you can't figure something out, like how to make soap, there's probably a detailed wiki and a several year long running story that someone still updates detailing how to do it and how it all went wrong and killed everyone.

RimWorld is very good, not as complicated, and much more mouse heavy.

You can, but realize it is a system focused game and in my opinion has a high learning curve. I would also recommend the Steam version rather than the free version due to the texture pack. I would also recommend playing along with a new players guide like Nookrium's https://www.youtube.com/watch?v=fGd_nAcmpnQ.

But the game is fully pausible and you can put it down and pick it up as needed.