You could always ad something like "the amazing house robot" "The house robot who saved the world" "Sandmans house robot"The house robot who malfunctioned-and-got-a-hold-of-something-sharp-and-pointy..." "The house robot with a soul" etc etc if you want to give away more of the synopsis then he beeing a house robot.
About the design itself i dont have anything against anything in it. It all comes down to how much you want to reveal about the movie, right now you know it's some kind of scifi, it's dreamy/magical, the chance of the robot doing something big unexpected and fatechangeing using his imbalanced house robot magical powers. If you speculate...
The concept of semi transparent enviroments over the gradients to show of more of the plot is always a possability, more "save the cheerleader, save the world" type text could do this also.
You may want to change his expression to fit the mood of the movie though with his current posture and expression you cant realy tell if hes a good or bad robot. This to give away abit of the movies ending, if you will walk out of the theater with a smile going "That was a cute movie" (Ofc it could still be a "sad" ending but aatleast something you are content with, im thinking "The Iron Giant" if you've seen it; Ending Spoiler:
) Or walk out like on needles after watching the firendly house robot go berzerk with a meat cleaver...
Also why do i keep making these kinds of long posts in the middle of the night...