I built a music theory course with games and spaced repetition

I’ve spent a year building a theory learning path that starts from scratch and goes all the way up to topics like Secondary Dominants and Borrowed Chords. It uses a combination of games, interactive lessons and spaced repetition to help you understand and remember concepts. Not just learn something new and forget it in a few days.

I’m trying to figure out: 1. Is the progression logical? 2. What am I missing that you’d like to see in there? 3. Where does it get confusing and could use more clarification?