Awesome that you're going to continue working on it. When you update, reply here so I can see the newest version! I've played some asteroids games that get real fun once you add in upgrades, etc.
Hey I just got a new version up that has the background and sounds fixed! I also added a bit of a delay to the beginning of the game as well so you're not immediately thrown in. I fixed asteroids spawning on top of the player too.