Make sure your game music is well crafted. I reckon in ranking of importance for drawing a player into an adventure and forging an emotional connection, they are:
3. Art style
4. Game mechanic
But what I really want to talk about is iMUSE - and how feasible is it to get that into DFA. If fellow backers don't know what iMUSE is, it was a brilliant interactive music engine designed and used by Lucasarts in their adventure games back in the 1990s. A good example of its capabilities was in DOTT, when you transitioned from one room to another, or even between characters (Hoagie, Bernard, Laverne), the music theme and accompaniment would smoothly transition. Like if say you were in Nard's time, and switched to Hoagie, the background music doesn't miss a beat while changing to the 'colonial-founding-fathers-times' style. Now I'd love to see this kind of technology being used in DFA. I just hope there's no patents problems....