I'm trying to do this whole graphic art thing again. Be as nit-picky and critical as you feel is necessary. I wanna git gud.
Mm... I like the colors and the fire effect. I feel like the null space to the right isn't serving much purpose—I would go ahead and extend the fire to the right edge. You might also consider making the lower part of Eren's torso more visible under the flames, as right now it kinda looks like he just stops at the chest.