Apparently this is only cheap on mobile. Somehow it only cost me $2.11 on Google Play, but it's listed as $6.99 now. I also spent $7.41 on the in-app upgrade. I'm seeing $20 on Steam? That might even be worth it, but is not cheap! Someone else would have to say if the modding scene makes the difference worthwhile.
Best $2.11 I've spent there! Here is a Cheap Games Android pro-tip: You can make about $1 per week from Google Play Rewards app, mostly from confirming that Google's GPS behavior tracking was accurate. So that's like $50 in "free" games and in-app purchases per year.
I could describe the game as "anti-idle pseudo-turn-based". Like Dwarf Fortress, you'll spend a lot of time with the clock on pause. Make your moves by dragging cards to the appropriate places, unpausing and waiting for the next event. I've always got the timer on double-speed when it's not on pause. Every 60 seconds, one new recurring event will recur.
So that all sounds kind of boring, but there is a lot of lore in the game. The fun is all in learning what is possible, figuring out how to survive, ultimately conquering an intimidating system and setting new, loftier goals.
Dragging cards around works really well on tablet, but it's almost frustrating on a small device like phone. I still spent a lot of time playing it on my phone when I couldn't use tablet, though :) I did things the hard way without a wiki or subreddit, that was a fun way to do it. First day learning curve is steep, pretty fun after that.