I recently completed the course Principles of Game Design, on Coursera, from Michigan State University. This course is part of the Game Design and Development Specialization.
I have reviewed the first course in the series – Introduction to Game Development .
This one covers how to design games – having game ideas, creating a story, characters and most of all good gameplay.
It is far less practical than the first, given its nature, although you are supposed to make a prototype of your game for the final assignment.
I took the free version, which unlike the first course, doesn't have quizzes and you can't turn in assignments (of course, you are free to make and evaluate then on your own).
One thing I particularly liked is that every video has a linked transcription. If you read faster than the video, on most classes in this course (which has little graphical supporting material, most of the time), this is much faster. The course also had plenty of links to books, articles and papers on the topics covered, many which great coverage.
The course was interesting, and I've learned a lot. The thing is, one of the books they suggested – Fundamentals of Game Design, by Ernest Adams – is so good that reading the equivalent book chapter always felt better than the course lesson. And as a plus for me, it was already included in Safari, which I already subscribed to (so it is practically free).
Of course, while the book is also filled with exercises, you get no feedback from it (but the feedback from the course, if it is like the first, is just from students, not teachers or TAs). You also don't get a certificate. So keep all of that in mind. In my case, I feel the book is substantially better.