As someone who would like to hopefully work at Bungie in the future, the interview processes look EXTREMELY hard. Here are some quotes by current-employees describing the process:
Daniel Hanson
The whole day was pretty intense. I think the interviews added up to almost 10 hours, and that's not counting the programming test and two phone screens that led up to the day. The morning interviews were largely technical by nature: data structures, algorithms, technical design. It was the usual technical interview fare, but none of it was easy.
Danny Bulla
The interview process at Bungie is intense, more intense than any interview I've ever had. Everything I knew about game development and playing games was analyzed. Bungie wants people that are as passionate about games as they are about making them.
Nate Hawbaker
The hardest part: The 11 hour long in-person interview. So much problem solving...
Note: These are from the Breaking In articles.
So, I know that the interviews LOOK really hard, but how much do you think they're NOT telling us? You know, the secret stuff...the...wet noodles.