For my animated abstraction, I wanted to make it as lively as I could. I somewhat accomplished this by making the outside squares move in a large pattern, while also playing notes whenever they change direction. I also made the middle area randomly change from filled to not filled. When this happens, it plays a sort of drum beat.
This is kind of hypnotic, only just when I start to space out something unexpected happens.
I think you succeeded in making your animation lively through the moving blue squares. Maybe moving the green ones too would help give the middle and bottom a little more liveliness? Changing them from filled to empty was a good idea and an interesting visual effect.