It may be more than possible to just simply name this one Bioware: they own this territory really, though of course, sequels have been picking up where the previous installment left off since sequels were a thing. This generation brought that to a whole new level, focusing in an unprecedented way on choices and morality. Bioware had a major hand at making this a mainstay with the previous generation's, Knight's Of The Old Republic. In this day and age where everything is a trilogy though, things can get a bit complicated, so, Bioware had a genius idea: Mass Effect's Save File, and the choices you made through your play-through are going to carry over to the second game. Minds were officially blown. I have something like 10 different play-through's for each game, and that's exactly what it did for gamers. It allowed us to say, "Screw perfection, I'll just get it the next time around." (I to date have not managed to get every single member of my crew out of the Suicide Mission...) This has been done for a few games now, and is looking like it's going to be an even bigger element to our next generation.