Idea: Derrick Freeland - Though I believe there could be a better expand to your idea, I think regardless, it's the least abstract of all the others, oraxon being second close.
Atmosphere: Ilyich - I just love that background
Design: oraxon - The whole coin stack deal, gave me a hitchhiker's guide to the galaxy vibe, and kudos just for that.
Composition: DrewCCU - Despite I don't like the blue part of the picture, I really love the rest of it. Even if most likely that's just a randomly drawn thingie.
Functionality: Ilyich - Not sure who could draw a character there, most likely you, but I can see that scene work easily with a nice fishy-like character.
Technique: oraxon - Well, i believe any of the entrants could fit there, but oraxon has always surprised me with his entries, varying a lot in terms of how they were built.