I'm going to work on the sea critter (detail, eye placement, eye color) trees (shape, touch up the ruffles to make them smoother) and I'll look into another color for the shirt but I actually like the one thats there now, but eh.
I made a few adjustments (fixed up the tree waves, gave a bit more detail to the sea creature, fixed its head and eyes a bit) and raised the placement.
I would have the shadows of the trees on an angle. For me that would define the trees from the shadows. I like the concept I would definitely wear this.