Color!
For my first time seeing you use color, you use it surprisingly well.
The robot does an outstanding job of conveying emotion, and your use of all darker, cooler colors (besides the bar on his head) supports this, as does the absence of color in the area surrounding his little "bubble". Stylistically, it follows suit with your normal, amazing style. I loved the attention to detail in even including the dots on the fret board.
The snow-flake is a nice touch, as well.
Wonderful work.