meh
First, let us point out you misunderstanding of how bullets work. The casing does not travel with the bullet when it is fired. Secondly, there is already a series very similar to this, except way better.; if you want to compete at all, you are going to need more than a few screen shots from CS and plain onld stick figures. You need to draw freehand in frame-by-frame animation. Third, the blood for the head shots was terrible.
I know that this is your firs animation, so you have plenty to improve on. At least you got the audio to sync. Oh, and get a start button. I think NG has some you can download.