I have had a similar experience to others here in that Mediatonic seem capable of requesting that you take time out to submit some code, but incapable of mobilizing themselves for an interview. The only reason I write this review is that I took the time to put together the submission. Initially I applied through an agent but heard nothing, I found that strange as I had worked in games but came with substantial recent Azure cloud development experience which seemed to match the job description.
I decided emailing them wouldn't hurt, they replied and said they liked my profile and asked me to submit an exercise. Initially I heard very little as the submission had to be passed to the right people to "review" eventually there was an admission that it looked good and they would try to organise a time to get me in. This simply never happened, from what I gathered getting the right people in to perform an interview simply doesn't happen. Weeks went by, then months, I think the time between the agent putting me forward for this role and the point where I eventually got hired by another organisation and let them know I was off the market was almost three months, which was the entire time I was looking for engineering positions on the south coast. I would advise others to be wary of this before spending hours on the test and if possible ask that an interview time is penciled in prior to spending time doing the work.