Could you enlarge the eyes on the top? I don't know if this is painted on or thread painting, but I'm sure you can come up with some small thing that will slightly change his expression.
Looks like my Koko when he is closely examining something he thinks might try to get away from him, like one of his toy mice.
I think it looks natural, most cats can look like this at times. And it is a good tribute to the Gray Ghost.