The pressure of game production is nothing compared to seeding the idea in the first place.
When Chair Entertainment first started, Creative Director Donald Mustard along with all of Chair’s other employees (all five of them) locked themselves in a room for two weeks with the sole purpose of coming up with as many game ideas as possible. From that exercise, hundreds of ideas were birthed and the best 20 or 30 of those ideas were recorded onto one-sheets for future production. Infinity Blade was one of those ideas.
Chair is known for games like Undertow and, the amazingly well done Shadow Complex. Donald attributes Chair’s success to a few simple principles. 'Find a hole in the market and fill it' was his philosophy when creating Shadow Complex. No one was really making Castlevania-ish, Metroid-ish style games for home consoles because no one wants to spend $60 retail for that kind of game nowadays. So that's why they made Shadow Complex in the style that they did and made it an inexpensive, downloadable title for home consoles.
As for mobile devices with touch screens, there were plenty of market holes to fill because this was (and still is) a new frontier for game development. A specific market hole in the mobile device platform was that there were really no gritty looking, hardcore graphics games. Mostly you just have lighthearted looking games like Cut The Rope or Angry Birds. This explains Infinity Blade’s dark graphical style. Donald Mustard goes on, "We believe at Chair that if you're making a downloadable game, that people don't want a cheap version of their favorite retail game. They want a unique experience." Which is yet another quality of Infinity Blade.
“If we could make a game where if I see an enemy swinging a sword at me in some angle and then I can swipe my finger to counter the swing, then that would be something I've never experienced before and the game would be fun.” Which is, of course, the unique experience of Infinity Blade.
Also, knowing when people would pick up and play games on mobile devices needed to be considered such as "On the couch while watching TV" or "While going to the bathroom" (let’s be real, we all do this) so he goes on to say, "How much of a rich gaming experience can we give people before their legs go numb!"
Lastly, they had to think about the fact that your fingers would be in the way of the screen when you play games on the iPhone or whatever. Everyone at Chair agreed that in order to solve this particular issue, they had to make games that can be played with only one finger.
Basically, the whole session acted as a gigantic service to anyone looking to put together games for mobile devices on how to consider what needs to be considered. It was actually very informative, especially to anyone who has developed or tried to develop games using the Unreal Engine before.