I like it a lot. But the tip of the tower touching the top edge of the picture is a bit of a compositional no-no, I think. It would look better with a wee bit more space above.
Mmm. Nice colors, and the forms work really well on the trees, but i feel like the waves against the cliff should be more angular, even within the confines of the seemingly circular style you've chosen.
Thanks for the comments guys :)
Yeah, there are a lot of issues with this, I saw most of them even before I posted. This is sort of just a "keep myself interested in pixel art" piece, so I probably won't change it for a while.