I ran into a glitch with chrome on OSX, hitting the enter key during the typing test refreshes the page.

Having a keyboard shortcut to go the next lesson seems essential, it is annoying to have to keep reaching for the mouse in a typing tutor.

I would like to see more 'nerdy' topics in the practice sections, stuff about programming, video games, passages from monty python skits, etc.

Other than that, I am really happy with it. I would gladly pay 10 bucks for something like this.