You caught me with this one at the first sight. It looks pretty good! Well drawn, well colored, well shaded. Not only the anatomy is right (for this cartoon-style) but also you can see expressions on their faces. The lines are fluent as are the gradients. The background colors are in harmony with the front objects and also tells you something about the cats personality. Even the shape of the patterns suit them very well. You could have made the eyes more shiny and maybe give them a bit more depths. This makes them look more alive for the eyes are a very important part of showing beauty and you have to shade/light them even better than the rest of the image. The brown ones eye you did best for you shaded it under the lid.