Chair, developer of such titles as Shadow Complex and Undertow, has been discussing the design decisions that went into creating its iPhone bestseller Infinity Blade.
Talking during a GDC session (reported by Gamasutra) company head Donald Mustard said that context was everything.
"We don't necessarily have the undivided attention of the player," Mustard stated, discussing that the game would be primarily played for short bursts during a commute. It also factored in another important issue - handheld players mightn't be wearing headphones.
"We had to design a game that you could play and have it be... an exhilarating experience with no sound," he says. "That was terrifying to me, to be missing one of my greatest tools ever, and still have to make a satisfying game."
Mustard also goes on to talk about the studio and its work ethic in creating downloadable titles. Its an interesting read, so check it out.