I just played the Lite (free) version, and it was pretty fun. Seems faithful to the original version... including the rather bland graphics. (Just teasing)
Nostalgia notwithstanding, it might be worthwhile to bump those up a notch. Maybe some 3D-looking balls and walls? Maybe some sounds? There may be an audience for the retro experience (old timers like me). But younger gamers might want something more visually exciting. Just a thought.
Either way, it's still fun as it is now. So I hope you do well with it.
Aside: I've always wondered where that lame name came from. Turns out Jezzball was named after the game entrepreneur
Jez San. He was apparently a friend of the author,
Dima Pavlovsky.
http://gaming.wikia.com/wiki/Jezz_Ball