Line blasters only drop in the two middle columns.
This level can be played by dropping the line blasters and using them to shoot to the side/s and remove metal boxes, but I found this used too many moves.
First use the blasters to remove the columns that the line blasters were in.
The metal boxes from the right slid over to be under the line blasters.
Now it is easier to remove them on the right side by blasting straight down.
Try to get all but two of the Pets down and hope that you can then work on releasing the butterfly/s
Remember that butterflies need at least 16 blocks of the right color to be clicked quickly (not too long between groups or the butterflies power down and you'll need more!)