Very cool. I like the animation. It gives you a sense of speed.
A few suggestions:
1. It would be nice if you could also show WPM. I looked it up right now and apparently WPM is usually calculated by CPM/5.
2. I'm not entirely sure if the CPM are calculated correctly. On the secret text I got like 75 CPM which can't be correct. I typed it in 12 seconds.
3. The contrast between the background color and the font is a bit low imo. Maybe make the background a bit darker or give the text a dark outline.
4. It might make sense to move the position of the cursor a bit to the left so one has more time to read the words ahead.