There's a good start to an actual game in here. I like the art style a lot and the character movement/direction facing/weapon use were flawless and worked as you'd expect. I thought it might have been a bit too easy as I just kept on racking up kills without having to move too much. If you think through your mechanics a bit more you could have a really cool game on your hands if you for example limit bullets, have the mobs drop pickups when they die, add in skills etc. I know that would take a while but it looks like you've got the base game down. Good luck with it and well done!