I think this piece could use a background. Eeven just a transparent background would make the rest of the piece "pop". The cat could have whiskers as well, altough those are tricky to make.
I like it. It could look more beautiful with cleaner linework (computer), and less obtrusive inside outlines (keyboard! your palette is missing an intermediate tone between black and the darkest grey). Also watch out for banding (cat's tail).
I like it. It could look more beautiful with transparent BG.