Loving it, keep up the good work. 
Only thing I'm not sure works is the characters black outline, think I would prefer a light/dark outline, as the black sorta blends with the background. Might be worth painting one of the characters outline and see if it helps or not.
But maybe the limited colour palette makes it hard to find the right tone?

Only thing I'm not sure works is the characters black outline, think I would prefer a light/dark outline, as the black sorta blends with the background. Might be worth painting one of the characters outline and see if it helps or not.
