Mini-boss time, and we have 40 turns to defeat the Giant Spider by throwing 28 snails at this cute monstrosity.
Right away search for nearby matches with the snails. Then focus on making special gifts in the main grid so as to hit multiple snails at once with rockets and explosions. Keep in mind that the bottom mini-grids will not work if the top ones are blocked by a Sticky Cobweb.
Magic Scissors can be fairly useful whenever there are lot of snails in a row without any obstacles in between. But if you focus on big combos in the main grid, constantly making matches and making room for more gifts to fall, then the objective is achievable in 40 turns or less.
The Giant Spider will send out Cobwebs on your special gifts faster than you can match them. Use that to your advantage by stacking up gifts, in preparation to be used with each other. It will take a couple of turns for you to release them, or for Cobweb wear-and-tear to free them, and in the meantime, they will be guarded against accidental matches or explosions.