Ohhhhhh there's so much I have to say about this game!
First of all it's definately my favorite so far out of all the games I've played, including mine. And it's the first game I've played after I've gotten the full experience out of it. I made it to level 13 before I had to stop myself from continuing, or I'd be playing it all day.
The CRT effect is fantastic, it really fits the game and just looks flat out amazing. The screen shaking is really good too. The music and sounds were great and substantially added to the game and made it a better experience. The shop was good too, although I think it could have had some more options or had more stages on the current ones. It didn't take long for me to max out my ship.
One of the only things I disliked about this game was how easy it was. I was able to survive extremely easily after the second level when I got the triple laser. I feel that if you had either added some more options in the shop and/or made things more expensive it would have lengthened the game a bit.
Also, this is a bit of a nitpick, but it bothered me a little that the screen didn't wrap. In the original Asteroids, when you went past an edge of the screen, you showed up on the other side. I do understand, however, that this would've been somewhat hard to achieve successfully because of the asteroids randomly spawning past the borders to keep the game going.
In the end I thought this game was fantastic in all aspects and I really enjoyed playing it. It's also nice to see a fellow Java developer doing Ludum Dare. :)