The eyebrows and the eyes in the expression sheet seem a little static. For example: Usually when someone is shocked with their mouth agape, their eyes widen. Seems to be the same with the eyebrows for 'sad' and 'smiling'. When someone is sad, their eyebrows would typically arc downwards in a gradual 'U' curve and the opposite when happy.However, I love the overall design of the character. Glad to see you didn't go for the typical brightly-dressed clown with a big, red nose and in huge shoes.
I was just thinking the same as Tom. The character is brilliant though.