Almost two and a half years ago, Soren Johnson did a long, in-depth interview with me and he just released the second part of it (both parts linked below). Part 2 covers the beginnings of Fantasy Strike, Yomi strategy including what to do on the first turn, a little about Pandante’s updated version, Puzzle Strike’s emphasis on player interaction, Puzzle Strike and Codex’s solution to free-for-all games, and the toughest design problems in making Codex.
These are long and go into a lot of detail.