I love just playing a game and seeing where it ends - but fighting for an achievement has certainly made me play 100's of extra hours inEuropa Universalis. There is just something about getting that 0.something% achievement, it sets a goal in a game that is in any other way "not winnable".
For this game, there will be little "historical" context. Most games have the "finish the game using x victory" and "finish at difficulty omega" - those are rather bland. I want to be the proud owner of 5 insect xenovassals as an avian, making them my imaginary livestock - and get a shiny thing in the bottom right of my screen for it! With a cool pun ofcourse.