Old Friends

I don't know what it's called, but I often see this type of style being often used in animation illustration. Shapes are clean and shading relatively simple.


I did a similar one before , but only did recently became more fond of this type of work. 


Anyhow, do tell me what you think as I hope to do more of these. 
Is the yellow tint unnecessary, or do you think it should cover the entire background? Are the colors harmonizing well? Any which you may think I can improve on.