Watch the video (with slides) from SGC 2015 here: https://www.youtube.com/watch?v=CuoR3xmSQ2w
In this talk right from the trenches, we cover several stages of adventure game development, including conceptualization, story, game and puzzle design, programming, voiceovers, music and production. Elroy and the Aliens has been in development for about two years, which has produced a lot of useful tips, tricks and lessons. Many of the areas covered will be generally applicable to all (especially narrative-based) games.
This talk was first given at the Slovenian Games Conference in 2015.