I love the colors! I think it's fantastic!

Allright thanks for the reply, this is really usefull. I'll keep it in mind next time.

The greys seem under-affected by the strong red light of the sunset, which makes them look a bit out of place, like they don't exist in the same space as the rest of the environment. More purple in the shadows and more orange in the lights would help, I think.

This is probably just a personal taste thing, but I think this piece could use some anti-aliasing, at least along the starker dark/light edges. Most of the colours within each object are low-contrast enough that things look smooth, which makes the aliased boundaries between different objects stand out more and feel a little harsh.