Im just at the beginning of the game. Playtime is about 3-4 hours.
What i can say for now is you are following the storyline when move around the map.
There are many locations at the start area you cannot reach. Closed doors, barriers and such things.
So movements are limited. You cannot go wherever you want.
When in town, you can talk to the people that lives there. Some of them have quests.
In that case the person (The house, you see the town houses, not the poeple) is marked with an " ! ".
If you chose a quest you may go further on the map, reaching new areas or unlock some doors with
keys you optain for those quests.
Sorry my english is not the best, but i hope that was helpful.