Overall, it was a multi-stage interview process. It started with a zoom meeting with a Unity Recruiter (who was great through the whole process). After passing that, they had me conduct a coding test on the codility website. The test consisted of two questions and you have a 1:30 to accomplish them. From there, I had face to face interviews (well in my case, due to covid-19, I had 4 zoom interviews). These consisted of two coding interviews with other software engineers, a design interview, and then an interview with the hiring manager. Each of the interviews were an hour in length. After that I had a subsequent talk with the group engineering manager, my references were checked, and I was offered the job.
The interview questions were difficult but fair. I highly recommend reading books like "Cracking the Coding Interview", and practicing problems on sites like leetcode.com to prepare for the interview.