I've posted clearly, throughout this thread, what the principal differences are:
*GM authority over backstory and setting;
*An important activity in play is for the players to declare relatively low-stakes actions that will prompt the GM to reveal setting/backstory details to them;
*As those setting/backstory details are revealed, the players will be able to conjecture (with more or less confidence) as to what is at stake in the situation their PCs are in;
*The players will try to overcome the challenge/obstacle that the situation presents, so as to win whatever is at stake - this will consist in some combination of manipulating setting elements revealed by the GM and using mechanically-defined PC abilities;
*As the players overcome challenges/obstacles via the play of their PCs, they get closer to the "finish line" which is the attainment of some or other overarching goal.
This is a very, very mainstream approach to play. It's well known. The most recent poster to describe a version of this play in this thread (I'm somewhere around post 20040) is
@Emerikol. But Emerkiol is not the only poster in this thread to approach play in basically this fashion.