The piece has good readability and I like the composition. Since you asked for feedback:

- It's not clear where the light is coming from, which is problematic. The clouds indicate that the light is coming from the left, so the right side of the island should definitely have darker shadows. The vines should be darker on one side of the tree than the other.

- In general, more contrast would be great!

- The perspective is a bit challenging because we're seeing the island from above, yet seeing the top of the tree from below (no branches are hidden by leaves). It's kind of a fish-eye perspective but there's not a gradual transition from top to bottom.

- This piece would definitely, definitely benefit from larger clusters on the grass, tree and dirt. Instead of using individual pixels or tiny lines to create texture, it's better to create larger chunks.

Hope this helps!