Thank you my friend. It didn't occur to me the idea of a common color. I'll try to remember your suggestions for my next landscape work, and thanks for taking the time to criticize my work.

Since this has not received any feedback yet, I'll share a few of my thoughts. I think it's great that you've started with a small canvas, and although I don't particularly like the combination of brown, jade and gameboy-green, there's something interesting about this combination of colours none the less. I only wish that the sky, the castle and the ground had some colours in common, to make the piece feel more cohesive and less disconnected. So definitely keep playing with colours like this, but maybe look for ways to tie them together.

I really like the unusual shape and design of the castle, but I'm having a bit of trouble getting a sense of its shape and the angle of the walls. There's also a lot of detail that just become noise, because I can't "read" what shape they're supposed to be. Noise isn't necessarily a bad thing, but if you're trying to learn how to do pixel art, I would practice on cleaner designs with less noise, because it'll make you better at adding small details in the long run.

These are just my humble suggestions. Don't put too much stock in what I say. :)