The graphics have come a long way from the early PC games. Now everything is very fluid and smooth. The details are so well done that you can now specify a cat breed and even the little pictures for selecting the breeds are quite distinguishable. I particularly like the little things that they pegged just right on cats. When you throw the mouse for the cat to catch, after it catches it, it paws at it playing with it, just like my cat does. Someone put some time into watching cats and mimicking their movements very well!
Leaving the volume up will give you some really cute sound effects. The cats meow when they want attention, which is helpful to know. My favorite has to be the purring. When you scratch them enough, they'll start purring. Keep going and they'll even start dancing while you rub their bellies, purring even more. But if you need to keep your game quiet (like when you're playing at work), you don't have to have the sounds on to still play, which is nice.