This is a Unity prototype of a dynamic world that's the center of a small game I'm currently working on. I'm now porting the project to UE4 which should be pretty fast, but in the meantime I thought I'd share.
This system provides an open world experience while allowing us to tell a very linear story and have it not feel forced. The player can walk in any direction they choose, but once certain conditions are met the next chunk of world that instantiates will contain the characters or setting for the next beat of the story. If you turn and walk the other way you'll find it appearing in front of you again. The story is, in part, about unavoidable events in a person's life and I think the gameplay mirrors this nicely. You seem to have choice, but in actual fact what happens to you is already predetermined.
Here a system of slots arranged in a hexagonal grid maintains the pieces that you walk on, and can choose to instantiate a special tile from a queue if the conditions are met.
Ignore my awful designer / programmer art and the hideous Unity default character.