Hey its i little bit like my idea. But better than my one 
It's so funny! :) Perhaps, it can look much better if you divide the ground into two parts, a distant part and a close part, and then the distant part was moving more slowly. Well, I don't know if I could explain well. I'm sorry for my poor English...
10/29
I'm relieved you understood me. Parallax...I've got it! Thank you for teaching me!
Thanks guys! I actually wasn't planning on entering this challenge but when I had this idea I decided to try :)
Merino, yes I understand what you mean. The effect you describe is called parallax. I considered it, but given the small size and how I was already at color limit, decided not to.