Not bad at all Sol. If I were to ever make a game, I doubt it would look half as good. Especially not my first. It was fairly easy, but it was also very addicting. vamp up the difficulty a tad, and maybe make the enemies something other that a circle. I.E. give each type of alien a different ship or something. which would probably also increase difficulty, as you'd have to aim a bit more. Over all, nice game. Especially for your first. 5/5
found a slight bug. if you die and continue to play from the game over screen, it makes it possible for you to proceed to the next level. thought you might want to know.
made it to level 6 on my first try. decent game. fairly challenging. i agree with crazed though. you should add a background of some kind, maybe spruce up the enemies a bit, and find a simple BGM track or two. but, over all, i enjoyed it. well done