Great idea, but an advance warning based on the earliest videos: it's windows-based programming. Just in case that puts you off (which it did me, I'm afraid).
Will the game support multiple platforms?
Yes! Windows will be the first platform, since it is currently the most
common gaming platform, but the series will later cover (at least) Mac,
Linux, and Raspberry Pi. Portability will be a major topic in the series,
so all the code will be structured to demonstrate how to write code that
is easy to port to new platforms.The situation is much better than it was 5 years ago and it is certainly possible for people to develop games without using Windows.
I am not sure if they've kept up or not, as I haven't kept up with the series, despite my attempts. Nothing against the series, I just haven't taken the time to follow yet.
Casey recently added a github repo (with auth) and so it's a lot easier to keep up with the changes.