This game is so huge. You have so many quests to complete that it probably will take you hundreds of hours to finish them all. As Inquisitor, you meet so many NPC along the way and you talk yo so many of them and from that you learn all about different tribes and empires and so on.
You can choose three companions, each of them with their capabilities. You have uncharted territories to reveal; you can choose any path you want. You have Skyhold, your centre of command which you can customise in any way you want. You can upgrade you gear, you can buy it, you can upgrade weapons. You can romance with your female companions.
The game resembles DA: Origins and the gameplay is almost the same.
Sadly, it's not a perfect game. It has its glitches and flaws. Sometimes the lip synchronizations don't work.
The graphics is not at its best.