Red is more eyecatching, but imho color palette is something that should relate to the general narrative/mood of the game and is quite hard to make an informed decision without that info. Same with the human or dog thing, I don't think one looks better than the other, but one might be more appropiate than the other.

Hello! My name is Ananda Cansino Arán and I'm a traditionally trained artist who works digitally now. My main strength is on environment concept art, as I enjoy worldbuilding more than anything else, from high concept and moodshots to figuring out details, props and functionality of the designs.
I'll leave here a few images, you can check out the rest of my portfolio at http://www.anandaaran.com and reach me at [email protected] if you think I can be of help.
Cheers!