Impressive, and interesting, but with one problem: I, like a lot of people, have floaters in my eyes (http://en.wikipedia.org/wiki/Floaters). When I focus on a single point and don't move my eyes around, they tend to congregate at the centre of my vision and in Spritz's case block the words that are being shown.

Potentially, a brief pause every 50 words or so would make sense in order to quickly move my eyes and unblock my vision, though obviously at the cost of some words per minute.