Interestingly, the top mistakes I made were due to trying to "correct" grammar in this jumble of words (ie, the wrong there/their near a noun) and flipping similar sounding letter combinations (ie, typing "ov" instead of "of" or "where" instead of "wear". Also, my first score was about 50. That was when I was just looking at each word and typing it. When I started reading it has a sentence and reading ahead (like you would if you were typing your thoughts or someone else's), my score jumped. Interesting.
EDIT: I tried again with a faster computer and actually being awake: