... uh...
>= Warning! Long and extensive review! <=
Was this actually 12 fps? Try at least 18... hopefully 20
First I'd like to say, there are definently some graphics that could have been fixed quite easily. For instance, if you're going to use lines for bullets, they should not be short lines moving forward, they should be long lines that extend from the gun's barrel to the point where they hit. Then the next frame should be a dashed line, and then they're gone.
I suggest making it faster paced with smoother animation. Also the "fast moving effect" with the paint brush scribbles was not only that fast, but didn't really look that good. The first time I saw it I thought he was being engulfed in something, but then I figured it out...
You also kinda need work with the music/sound better. Like when the slow music starts, you should have first given a pause in music with just slow mo sound effects or something, then kinda fade in the music.