Bend Research interview questions

I had a 30 minute interview at a recruiting event. Then they flew me to Bend for a full day of interviews. They paid for everything for my trip there. It took almost 2 months from when I applied until my interview. The on-site interview lasted from 9-3, and I had about 10 half hour interviews throughout the day. I had to submit a writing sample before I went. Every other interviewer asked me a few technical questions. A couple of them even only asked me technical questions during their interview. I was not prepared for this because anyone I had talked to said they only asked a couple really easy questions. I think the technical questions would have been okay if I had just reviewed a few key concepts. I think their interview process is getting more rigorous.