Since it's an open world game, with optional late game grind for legendary items, the play time can vary a lot. But a lot of people play for 50+ hours to finish all content.
The game is still in development and will receive new content for several more years. The main story is not finished yet, but you could say that it currently stops at the end of a chapter in the story.
I have played this game for 33 hours and I have lot of quests complete, there ste only missing those three girls in chalenge floor in spire of courage and one of helhonds and I do not know how to continue. But there is possiblity, so I will end it under 50 hours.
