Hello, im new to this forum and to pixel art, and i seek knowledge and help. Me and my mate are starting a game - something like contra, and i took the oath to create the art for it. It should be simple, easy to animate and so on. My first sprite is the main character and it looks like this:

But it doesnt look right for my eyes, and i dont know how to add more detail to it, while keeping it simple to animate  . Any advice? You are free to edit it with explanation what is done wrong.