The first step of the process was a written design test, which I was given 1 week to complete. It asked several questions concerning the game series I would be working on (ex. how I would solve certain problems).
After completing the design test, I had a Skype interview with two members of the team. The interview starts with simpler questions, but eventually moves on to design-focused questions intended to test your ability to analyze their previous titles, and your ability to come up with creative solutions (they're not called Mundane Assembly!)
While both the interviewers were respectful and kind, this was one of the more rigid-feeling interviews I've had, with things being taken pretty seriously.