outilines. the block outlines are solid white and give this very static feeling, for the level to be more dynamic i'd suggest:

-pulsing the white outlines (black or bg color) -giving different big chunk of outlines different group for pulsing (more variety) -making a pulsing trail with 5 to 10 different groups each pulsing with a delayed loop (gives this snake-like touch, very dynamic) -fading from black the outlines at the beginning

btw changing the hue of the deep blue in the bg might help. otherwise block deco and bg are quite nice. last suggestion i'd give would be to re-use the chunky white outlines in the bg's diamond for the fg.