The keyboard arrows at the top of the site are useless to use in the down direction. Once you click on down, the page scrolls down and they go off the screen. So effectively you can only press it once.
The Up arrow key is even worse: The only time it's visible is when you are already at the top of the site, and can't scroll up anymore.
The left & right buttons are redundant for the buttons on the left & right sides of the screen. I'd recommend removing the keyboard keys altogether since they take up significant prime screen real estate.