There was an interview with former Retro studio employee Mike Wikan, who gave some informations.
Apparently the work for the original Metroid Prime involved some really bad crunch at the time. As Nintendo became aware of this, they took control and switched leadership. And that new leadership stopped the crunch culture.
It is nice to hear a story for a change, that a bigger company stepping in changed things for the better. I hope more managers in the industry realize that crunch is bad for the company, bad for the people working there and bad for the games. The crunch culture needs to stop. Thankfully Nintendo did that at Retro Studios. At least if we believe that employee.
Also this makes waiting for a delayed game much better. Because I know, it is for the well-being of the great persons creating the game I love. They deserve a good work-life balance.
