I used the mouse to navigate the menu (ie. have a look at the available options and then start a new game) but then I had to switch to the keyboard to set the difficulty level and where to start from (the beginning in my case, since that was my first playthrough!). Plus I could not start the game without confirming each option (I was fine with both) by hitting the spacebar. Maybe you could let me use the mouse also there, and let me click on the "Go!" button right away.
... and maybe it's just me being too fussy ^^;