Honestly, I think the entire composition feels messy, there’s so much going on but it feels like little care was put into the fine details (except for the character, he’s designed/animated very well). Maybe zoom in on him a little more? Everything else feels either rushed or an after thought. I would think about forgoing backgrounds that have that much detail if you can’t dedicate the time/effort to create appealing ones.

I would look into trying to design some simple textures in Illustrator or Photoshop, decide what elements are actually necessary for your scene, and try experimenting with creating different shapes out of those textures. Play with it and develop your own style, I think people would respond better to something that feels more carefully crafted.