I would approach such a course by covering the basics of design, development and production in conjunction with practical exercises:
- The core interactive game loop between player, input devices, computer, and output devices - this helps cement the idea that it's important to consider all components of the game loop when formulating a design, especially the player's ability and motivation.
- Mechanics (the building blocks), Dynamics (how mechanics interact) and Aesthetics (coating dynamics with emotion).
- How objectives married with constraints provides challenge. How goal conflict arising from divergent objectives creates interesting challenges.
- Using progression loops and difficulty curves as methods of introducing new mechanics and challenges.
- Types of performance reward and the criteria that unlock them (typically accuracy, speed and consistency of challenge completion).
- The stages in production pipeline: planning, development, testing, publication.
- Planning and communicating a concept: how to use diagrams, flowcharts, spreadsheets and written descriptions to capture your concept and share it with others.
- Organising a project: folder structure (I like to use the ABCD system: Assets, Builds, Code, Documents); naming conventions etc.
- Estimating scope: getting into the habit of planning ahead and setting realistic targets.
- Useful tools: project management apps, art and audio packages etc.
- Construct 3 overview: the key features of the software; how the event system works.
This should give the students a solid foundation from which to build simple games. The topics can be drip fed into the course as and when they're useful rather than overloading the students with all of it at the beginning.
I would allow the students to pick one from a selection of the example or template projects from the C3 start page and help them modify and develop that into a complete game. In individual lessons I'd focus on how to implement useful reusable components such as score systems, health, lives, timers, levels, splash/menu/pause/results screens.
Depending upon available time and the ability of the class I would introduce more complex but very useful features of C3 like functions, arrays, dictionaries, families and containers.
Finally I would cover adding "juice" to a game - using audio and visual effects and animations to enhance player feedback and make your game pop.
Ideally I'd aim for them to have something that can upload to the Scirra arcade by the end of course, so they can share their efforts.
Hope that helps :-)