Serialized, very controlled interview process beginning with low level employees all the way up to high. They seemed very careful to avoid exposure to actual employees -- quite a contrast with other places I've interviewed with, where they really want everyone to get to know you who you might be working with.
It's obvious that some of the employees have a nervous, beaten-down air to them. Like they're being underpaid or overworked or something.
They also are extremely vague about what you'll be doing and who you'll be working with and what the work process is like. It's almost as if they want you to agree to the job and then they'll reveal all the ugly details hoping that in the euphoria of landing the job, you'll just take it all in stride.