What I like about FTL is how it works with the story.
My favourite examples are Elite Dangerous and Dune.
Elite Dangerous's FTL tech is based on alien tech and that allows the developers to do cool stuff that you wouldn't expect in an mmo (this is usually a loading screen so when this first started happening people were terrified).
And Dune's idea of having the entirety of interstellar civilisation dependent on one substance that can only be made on one planet, which also has other uses extremely important to different groups, sets the stage perfectly for what happens in the books.
ck2 is free*
If this was a multiplayer test, it would literally cost nothing to play other than a computer that can run a game from 2012.