The whole interview process lasted from May( Initial Application) to August(Rejection). Mind you, with COVID there may be reasons for a longer than usual application process.
I applied early May after finding their listing on Handshake. From that point, I did not hear anything from GM until mid June, where they asked me to reapply as they seemed to have switched from whatever hiring portal they were using to Workdays. After reapplying I was contacted to do a couple of cognitive games testing spatial and simple mathematical concepts and record 3 ~<=3minute videos in which you are asked a STAR question. Note for these videos you are given a chance to resubmit so there is less pressure to get the video as you want it off the bat.
Presumably if you pass the first round, for this position, they ask you to complete a coding challenge. They are not necessarily a difficult challenge, but if you are not used to Leetcode-type questions, you should be prepared for it. You're are given the question on their online IDE and can choose from a multitude of the more common languages to use to solve that question within 30 minutes for each question. I did find some difficulty in submitting a question because of lag, but I am not sure whether that was due to my own internet or the website. That being said, they were LC-Easy type of questions.
Afterwards, I was contacted by a recruiter/HR to schedule a 15 minute phone screening. This was the last time I ever got a response from an email sent to anyone during this process.
The phone screening was typical, telling you a bit about GM and then asking if you had any questions.
After the phone screening, I was contacted to schedule a Skype video interview with two Senior developers from two of their offices, which are the Michigan, Arizona, Texas and Georgia locations. Again, once I sent the email to schedule the interview, I did not receive any other communication from the any of the recruiters.
As for the two interviews, they were as other reviews say, laid-back for the most part. The two interviews consists of 15 minutes of the interviewer going over your resume, 30 minutes of STAR type of questions (with the second interviewer mixing in a technical question or two) and then finishing off with 15 minutes of you asking questions.
During this part of the interview, however, I do have to say I had a negative experience with an interviewer which is one of the reasons I have to rate the overall experience as a negative. I felt that they were talking down to me, which should honestly not be a thing in a professional interview.
Regardless, I finished the interview and they told me that they should be in contact within 3 days, max a week, and if not that I should send the recruiter an email for any status updates. This is the second reason as to why I rate the experience as a negative. It may be due to the multi-national corporate nature of GM, but I never got a response from anyone for any type of email. I emailed my recruiter to see if I could get the emails of my interviewers so I could send a thank you note, no response. I emailed them after a week past to see what was my status with no response. It was only after 3 weeks that I finally got an email at midnight saying that they have decided to move on with other candidates.
Frankly their lack of communication was rather frustrating and unprofessional in my opinion.