I was told that my previous key visuals are too bright and colourful for the mood and tone of the film. After the animation session, I've worked hard to explore what the film's appearance should be. For me, Autodesk Maya is still difficult to understand and time consuming, especially when I try to learn new things.
Anyway, I got this one after many attempts in lighting and rendering. It still needs an improvement. I will seek more tutorials.
EDIT: I have moved on to do test composite in order to check that all of render passes is enough. As you may see, it has a problem about lens blur. I'm going to fix it ASAP. Lacking of familiar AE plug-ins generates difficulties in getting what I exactly imagine.