So the Red Bull caught them...

I can definitely tell that there is a story behind this landscape--it seems to be from another world, and it makes me wonder what kind of awesome creatures live there! I like the color palette you chose, especially for the water.

Having no experience with deviantART's muro program, I don't know how much freedom/choice you have when making a picture. So, I'm assuming it's pretty limited, in which case you've done a really good job! I think the main critiques I have are that there aren't enough variations in the textures (water and sand and rocks are all different in terms of how smooth/rough they look) and that the sky has no shading (which makes the picture look a bit unfinished. If you could play around with the brush settings, I think it would be good for you give the rocks some more texture, and the sand too (maybe by adding more colors or little speckles to it?), and to add some shading to the sky. Or some stars!

For a landscape, this is a great start. I'd love to see you add some characters to it to help fill out the story you're telling! Keep up the good work