This is a brief introduction to game design by Dr. Lewis Pulsipher (see Wikipedia), designer of several published games (e.g. Britannia), retired teacher (computer networking, later game design and game production), and author of the 2012 book "Game Design: How to Create Video and Tabletop Games, Start to Finish" (McFarland).

A much longer and more comprehensive course ("Learning Game Design") is also available on Udemy. 

(This course was free in 2013; it has not been free since then.)

Comment from LinkedIn:

"Fantastic course, Dr. Pulsipher. I'm in school for Game Dev (which, of course, does involve programming), and while my last instructor is a veteran in the field, the textbook didn't emphasize the required aptitude for Game Design. This one nails it without sugarcoating it." By Michael Thompson

A recent reviewer (Santiago Eximeno) gave the course 3 stars, so I asked him what I could do to improve it. He said:

"Your course is fabulous. I have given it 3 stars because it's a first step. I really enjoy contents but, as its name says, it's an introduction to game design and I think that a wannabe game designer must continue studying and working on it.

So I don't think that you must improve this course, it's just that for me is a first step and for that I have given it a 3 stars rate.

I'm sure that "Learning Game Design: as a job or a hobby" (I have starting it now) will be great . . ."

And it's certainly true that this course is only a start.