Your game was pretty good overall. You took something that has been done to death by many beginner programmers and changed it a bit. At first I thought that it was another pong game, and a bad one at that. It changed to the real game fast enough that I didn't get bored and quit.
The audio does what it should, it could be a lot better, but for the level of the game, it does its job. I'm kinda happy that there wasn't some annoying explosion noise, or shooting sound in the game since it would have gotten annoying quite fast if they weren't "just right."
The graphics aren't great. Obviously it sticks with the pong theme which means that it's intentionally a bunch of boxes rather than more detailed enemies. The explosions weren't too big, they weren't amazing graphically but they did their job.
Gameplay is quite primitive, but I like that you can still use your paddle to deflect enemies. The laser is good as it is since you can only fire two at a time, but they will go through everything. If there was an unlimited amount, the game would be to easy, but on the other hand if it was unlimited but only destroyed one block the game might be balanced, but much more click intensive.
Replay value really isn't there since once you've played for about five minutes, you've done everything the game has to offer.
I think you did a pretty good job, you kept the feeling of pong, while taking it and doing something different