Diablo: How the Original Game Became an Action RPG

HN considers it one of the best GDC post-mortems, with funny anecdotes (such as turning down Hotmail equity) and multiplayer insights.

David Brevik's GDC 2016 post-mortem of the original Diablo, covering how it evolved from a turn-based claymation DOS game into the genre-defining action RPG. It includes development anecdotes and lessons learned.