Sorry I wasn't online during the process of creating this piece >.<
First of all: nice clouds in the bottom! <3 (those in the top should look a bit different to my mind, it all is about the highlights). And the composition with the angle are done well :)
There's smth that bothers me about the shadowing his tentacles: the one to the left in the bottom looks a bit strange. I guess, it sould have more shadowing (will send you an example).
And overall it's a good job! Keep it up :3