Since id imagine quite a few of us are going to put a lot of hours into this over the past few weeks, I think it'd be a good idea to backup your stuff in case of your power going out/pc blue screening/etc and corrupting your project files! Someone recommended this on the r/gamemaker subreddit
This is a very, very thorough backup regime but i've only tried the program i linked below (with only one backup)
It isnt open source (but the free version isnt a trial and has no ads as far as i can tell), so use at your own risk, but I just did a test backing up my game maker project and it worked fine. And only took a few minutes to set up.