I really like the art style and animations. It gives off a Pizza Tower vibe, which is what it seems like you're going for with the title card and all that.
My issues are: there are no sound effects for hitting enemies or getting hit, which makes it kind of hard to tell if, well, you are hitting enemies or getting hit. The "spark" effect when you shoot falling down instead of fading away or something like that looks a little strange to me. The bullet guys come way too quickly and their hitboxes don't really work right. Finally, the shooting feels REALLY slow. I think I'd prefer the time to shoot again to be shorter.
In addition, I'd suggest possibly making some of the enemies take more than 1 hit to kill.
Overall though, this is a good start, despite how negative my review may sound. I think this game could be really cool when it's finished. I wish you the best of luck!