1st Prize | #Ikramine_contest in Instagram

I see what you're going for and I think that is impressive. What you were trying to do in this picture is show a wide perspective, with both the things in the background and the character's in the foreground being the main focus. This is difficult to pull off, usually these type come off as "Where's Waldo?" pictures or put the main characters as the main focus, making the background into a huge mess.

The colors are aquatic, ocean based with different hues of blue, making the jellyfish stand out more. The darker colors contrast with the brighter colors , making it very easy on the eye. I like the underwater city in the background, but it could use darker tones to it. It looks a bit like a sketch.

As for the two characters in the picture, I agree with DEADANEX. The clash with the background and look out of place. Maybe a bit more realism would help. I do like the shadows on their legs, though, it looks cool. Keep up the good work.