operator

The 20 cyan blocks at 3:06 need to be kept. Removing the three green, blue, and purple blocks together at 7:44 is very effective; otherwise, you can't remove the blocks of three colors together.

The black and white blocks at 5:06 need to be removed. This needs to be done from the row with four horizontal white blocks in the middle. Therefore, the black block at 5:40 needs to be kept to remove the black block after the orange block.

The main difficulty of the level lies in removing the green, blue, and purple blocks together and the black and white block at 5:06.