I've actually interviewed with them twice, years apart. First time my resume got bumped by a contact, this time I only applied online.
Both were similar, where I met with the staff and we had a discussion about the job, work I have done, examples of said work, how I like to work, what are some challenges I faced, etc. There was nothing "tricky" about them and overall it felt like a relatively standard interview.
I will say that I never clicked with the interviewers. There was no conflict (I didn't think) as I found them professional and polite. But it also felt like there was less of a conversation and much more of them interviewing me. So I was unsurprised to have been rejected and think overall this is probably not a place for me. I would actually like this style of it being a workplace (vs. enforced friendliness/team work vibe, etc.) and they do good work but it just isn't meant to be.