The graphics and sound compliment the game. It's very good for the first game you've made and I enjoyed it, despite wanting to shoot everything that's on the screen even when I'm not supposed to.
This is definitely a good game. Yes I'm sure it could do more, but what it does do, it does well.
given that this is your first game, it isn't bad. the graphics and sounds are pretty decent. The concept is alright I suppose. Could use some more levels and a bit more challenge.