Wow, this one really surprised me! It ain't winning any awards for beauty or anything like that, and the concept ain't exactly deep or unique, but something about the game was very addicting, satisfying and just plain ol' fun! A good example of solid level design and core game feel winning out in the end over pretty graphics (though it did still have some nice effects for death and the shockwaves, for example).
If there were any issues I had with the game, it's that I did feel like there was some confusion over how the shockwaves work. Because the shockwave graphic shows the shockwave fading away as it gets larger, a player could easily think that the shockwave loses strength over time. However, it seems like the shockwave, no matter when it hits during its expansion, will always hit the ball with the same initial strength. I didn't mind it when I realized this fact, and I liked the consistency, but there was some initial confusion where I thought I could tweak the power by distancing the shockwave.
If there was something I felt was missing from the game, it mighta been a score system like golf where you get more stars or something if you win a level with minimum strokes, or shockwaves in this case. But I had fun trying to go for minimal strokes on my own terms, haha.