So here are the steps I'm considering:
1. Collect curricular ideas and lessons from high school teachers already teaching the subject (game design/development).
2. Look at college-level curriculum and syllabi to get an idea of what colleges are doing.
3. Read up on theory and practice of game design to understand the field
4. Determine what software I will be using (kept limited to 1 or 2 modeling programs and 1 or 2 game/animation programs).
5. Learn the software on my own to a rudimentary level
6. Start the course with concepts (board and card games, etc.) with units that explore each concept in depth
7. Gradually introduce software and let students play with it to get a feel for how it works
8. Culminate each semester or the school year with games students have designed with the software
I think again that you are looking at game development generally, not game design.
Your step 8, the final result you hope students to get out of the course, is probably the most telling aspect. You want them to have completed a running game, not design a game.
Far more likely you are looking for an introduction to game development across all disciplines rather than only the single discipline of game design. My suspicion is even stronger that this is what you are looking for, mentioned in the earlier example:
Since you linked to successfully completed games by student, a broad game development across all disciplines, my hunch is that game design is probably the smallest aspect of the course that you will teach that age group. You will probably start with the basics of the tools you will use, then start with the content pipeline for getting art and animation in the game, quickly build up some simple levels. Then off to programming to give them the ability to bind the pieces into something useful. Then will be iteration on all of those, the content pipeline, tool usage, and programming, until they are able to actually construct something that holds their interest. Only after those skills have been developed are you likely to actually get into the barest fundamentals of design, of the psychology of play, of the understanding of emotion and fun, of balance and imbalance, of building precept upon precept, on crafting designs that can be reused, on building a small number of carefully crafted parts that are easily understood and enable depth of play.
If instead you want to focus only on design, I would run a course based on topics like the psychology of fun, the nature of fun versus mechanical tasks of the Skinner box. I would have presentations consisting of specific genres of games. Evaluate clips from the breakthrough games and disect what makes them so good.
Portal is awesome for being a continuous tutorial where you learn something and then apply it, learn something new and apply it, and continuously learn and apply a few basic skills applied in new ways. The Legend of Zelda family similarly introduces game mechanics one at a time. First you wander the world and learn the basics of that; then you get a sword and learn the basics of using it as new aspects of the world open to you; you gain another item, typically a boomerang, which opens new avenues of the world; you gain a new item, perhaps a hookshot, and new avenues are again opened. Each time you gain a simple mechanic and it transforms the world around you.
Evaluate psychology of games, what makes horror games horrifying? What makes toy games as toys? What makes a good card game? What makes a good strategy game? Why?
I would evaluate maps, and levels, what makes them good and what makes them bad, and why. Different genres need different things for different reasons. For games where you progress, how does the system facilitate learning and skill gaining and progression of the player? For competitive games, how can you ensure each player has equally fair positions? How can you ensure the game is continually unbalanced, no matter where you are you have a weakness that can be exploited, but at the same time every aspect has an advantage that can be exploited?
For story telling games, how can you communicate the story through gameplay? How can you tell story through interactive revelations, make the player experience the game through the eyes of a participant? How can you tell the narratives through careful design? What design choices enable story-telling, what limits your ability to tell the tale?
Again, because you have repeatedly mentioned a desire for students to finish the course with a completed game that they have built, I'm fairly sure you are talking about a course focusing a little bit on each aspect of game development. That means touching briefly on art, animation, programming, audio, testing, level design, each with enough depth that a student can create something cohesive as a full game. Once they've got enough building blocks from every discipline they can build their bigger trophy.
