Cool concept. As this appears to be a typing game I think it would benefit form a focus on the keys and the mouse acting as a secondary motion. If when you type the letter then the dice lights up it color and them fades. Allowing for the player to remember the colors and then use the mouse to remove them. Using the mouse to check the color while typing at the same time feels a little clumsy.
I love the art style, everything about the art style makes me happy. :)