Not bad for a first.

It's definitely a pretty good game, but there are some things you could do to make it somewhat better.

The graphcis are pretty boring. The menus are actually quite painful too look at, with the black background and the flashy fonts and stuff. Think of adding a cooler background, and a simpler layout for the menu. Some menu music would bee nice as well.

The hit detection is rather horrible. Both your bullets and the ships, they hit you before they're close and vice-versa. Another thing is that the game feels pretty repetitive. I mean, it doesn't change much. Or it changes, I just died before I got that far. More enemies as you progress, different enemies, like enemies that shoot back and can take more shots. Upgrades to the weapons, etc.

THe music should be on as the games starts. I like that you have amute button, a lot of game-makers leave that out. Maybe some options for music?

Just a few tips that could help you make even better games, or improve this one.