I applied online in November 2017. There were basic questions on the application form, such as why do you want to work at Mars or why are you applying to this program. Then I received a link to undertake online tests: numeric and verbal reasoning. Both were fairly easy. After the tests, a recruiter called to interview me with no prior arrangement. I asked to schedule our call, as I was in a meeting at this time. There were some basic questions, then the recruiter started asking questions in English. I wasn't quite sure the recruiter understood me, she had a strong accent and all she said after each my response was "that's nice". At the end of the phone interview, I was informed that I should expect to hear back from them in January.
After this stage, as the recruiter said, in January I was invited to the next stage of the recruitment process: the Business Game. There were around 80 applicants at this stage. We were all divided into small groups of 6-9 people. The task was to read a piece of paper, then start discussing and make a presentation to assessors. Although the process was supposed to be in English, our assessors asked us to talk in Russian. To succeed at this stage you have show your leadership skills and be as persuasive as possible, but not aggressive. (read about their culture)
In about 2-3 weeks, I was invited to the "Assessment Centre". There were 2 panels, each assessing and interviewing 7 applicants. The day was split into 2: presentation and interview. All of us had the same case and we had to make an individual presentation to the panel. 10 mins for presentation and 10 mins for Q&A. The interview process began in the afternoon. By the time it was my turn to enter the room, they were all tired. They weren't in a mood to continue and seemed like they wanted to be done with this asap. In the end, when I finished asking my questions, I asked if they have some questions left, the response was "We asked you", which I thought was quite rude.
I think if they arranged interviews on the following day or later, it would have been better both for the panel and applicants.