With near-perfect runs of squares, you can get stuck with one anchor left and one or two moves away from completion. If the level had fire, my phone would be a shattered mess at this point.
Clear the blocks downward as quickly and to the right as possible. You need to have almost 20 moves left once the first set of anchors are gone.
Squares are absolutely essential because the anchors only come with every so many rows cleared, so you need to be clearing all of a single color each time.
If you get stuck repositioning for more than a single move, I’d recommend bailing out of the game and burning a life. It’s not worth the frustration.