the background looks nice but the gameplay isn't that exciting yet. the background doesn't get influenced by the ball, right?

the music stuttered a bit but i was rendering something in the background with all cpu cores so maybe my pc was too stressed out.

you could look into the c# port of box2d and add some 2d physics gameplay elements. 2d physics games can be a lot of fun. a lot of stuff works better in 2d because it would be too complicated for the player in 3d.