hello, i see this already has a lot of potential, there is a good rainy mood, i can feel/taste the air almost, you have good atmosphere in it.
I would like to stress that its clear how you are thinking, almost like a 3d modeller starts with basic cubes or spheres, except you are just using those as shorthand for things such as the shoulder pads, they are like jelly beans or something
what i think would help you is to look at real shoulder pads, then think of how you symbolized them, and maybe blend the two, to create your own symbol for the thing. if you look at any established artist's style you will see they often have a few "rules" they augment reality with, to create their new stylized universe. if you like the look of round, bulbous things, practice understanding each and every thing you draw, and then apply your style to it.
also, it looks like he is holding a weird gun. he doesnt look like hes in pain, or reacting to having an arrow in his torso. why is he jumping? the scene doesnt make sense without your explanation. you need to create context for stuff like this. just moving a character upwards, and putting a shadow under him, does not create "jumping" in ones mind, just floating. think about how someone would jump, how their legs would move, how he would press onto the flag pole, how he would crumple if it was in reaction to being struck by an arrow, how to create context for the arrow being just shot (maybe extend the canvas and show scene from the pov of the archer or just over his shoulder?)
looking forward to seeing where you take this.