Interesting minimalist concept. I really like the shrinking/enlarging frame dynamics, because when the frame is big there is more space to maneuver, whereas when the frame is small, it is easier to dodge those green rectangles. It's an interesting and balanced trade off. Oh, the sound design is pretty good as well.
1. The game gets too repetitive much too fast.
2. Green rectangles seem to be slightly out of sync. If the white square is moved towards a green rectangle that just passed by, it still counts as a loss.