Pretty good.
Played this and Gravity Ball 2 through several times before. I like the whole concept of the games, and I even found a glitch in this one! While playing level 5, I got the "Wah Ball" powerup, the gray spiky ball that's not affected by gravity, and I'm not sure how it happened (It could be because there were also balls from the multi-ball power up in play), but a little bit later, upon colliding with the paddle again, the "Wah Ball" started acting like a normal ball, under the influence of gravity! Except for that during the whole time, the Wah Ball always passed through the moving block and the block that turns the lights on and off, without hitting them. Again, I have no idea how it happened, but it was pretty funny. The Gravity Ball series are two great games, and I hope a Gravity Ball 3 might come in the future.