I think your biggest problem as far as impressing people is that your game is Pong. Everyone has played a thousand pong games and games in general don't get much simpler (or more over done). As far as what I liked, your game feels solid (no immediately noticeable glitches, nice framerate, good overall look and feel), the asteroid mechanic definitely changes it up a bit, and I especially like the multi-touch two-player mode.
Add some options!
The ball is moving quite fast and at first, it caught me off guard. It would be nice to be able to adjust this myself or maybe have it start out slow and get faster. I would also like to be able to adjust (or atleast see a difference in) your main mechanic, the asteroid. Adding the option to change the number of asteroids (2+) would be great! If you don't want to allow the player to adjust these, you could adjust them yourself by adding multiple difficulty levels. On easy, the ball would move very slowly with 0 or 1 asteroids while on hard, the ball would move much fast with maybe 4 or 5 asteroids. Even the number of balls in play could be adjusted. I would say that some form of options is absolutely necessary for your game.
More game modes.
When I first played the 2 player mode (by myself) it gave me the idea for a "training" mode where you played against the game (instead of an opponent) to get the highest score you could. In this mode, you would hold the device landscape with a thumb on each paddle and keep the ball in play, scoring a point each time you successfully rebounded the ball (kept it in play). With this mode, the ball might get faster the higher your score got. Then, you could even add leaderboards for people to post their high scores too. Another mode could be an "asteroid destroyer" game where you played against an opponent or against yourself with two paddle (like training mode). The objective would be to destroy as many asteroids as possible, earning a point for each one. Every time you hit an asteroid with the ball, it would explode and another one (or 2 or more!) would appear until your ball escaped (entered a goal). Be creative and most importantly (IMHO), get as far away from simple pong as possible. You could make the greatest pong game with the best graphics and music and extras in the entire world and it would still just be pong and no one would be impressed.
I like your sound effects, but some simple backgrounds music could go a long way towards making your game feel more complete.
Many pong clones have them, they're fun but not original. Try to make you own, unique power ups that no one has done before! Power ups that manipulate your asteroids would definitely be original!
To summarize, your game is pretty good and has lots of potential! But it's still pong, and people have been playing pong since video game were invented. For your next game do something more original, you'll enjoy it more! As far as ratings and comments, don't let them bother you too much. Let your downloads do the talking.
As a side note, I would change the collisions of the asteroid so that it doesn't bounce all the way into the players goal, but instead stayed in maybe the middle 60% (or whatever you decided on). That was the only frustrating thing that happened to me to make me feel "cheated".