Certainly pretty.
First off, this game has style and a good idea. What it needs is more varied gameplay and a ton of polish.
The biggest problem is the repetition. Were it not for the music and me wanting to see all the graffiti and characters, then I would have stopped in 10 seconds. This is easily remedied with simple mouse minigames, like what you might find on elite beat agents.
You also have the unique problem of powerups being more boring than standard. Spraying all these neat little bits of pop art, or seeing the same few frames of animation for each structure, which would you choose? Instead you can unlock different effects or styles of art, switched by keyboard.
Obviously, you also need to fix the animation resetting every time you spray, and generally add more animation and atmosphere. The characters and houses are so colorful, but the background is like gray cardboard. And again, the art gets repetitive.
If you can make it fun, the style you have going could make it an above-average experience.