Continuing Robot project ( Unfinish)

Well I feel happy that I did much faster for the background ( 2h30) . But I will be done soon after asking my teacher for her opinion than I will finish it up!

Robot

 This is my first time producing artwork with digital .I spend around 15 hours to get to this far which is very slow and it's not even finish yet . I need to add a background that I have no ideal what to do with it yet .So I am very open for suggestions .
                                                                                                          Thanks