| Fire Works|
Used only Sunflowers and explosive plants!
Its name is a pun on the word "fireworks," devices containing gunpowder and other combustible chemicals which cause spectacular effects and explosions when ignited.
You should go to earlier levels to achieve this, as the number of zombies there would not be too overwhelming. Do keep in mind that although this is similar to Pyromaniac from Plants vs. Zombies, but you cannot use Wall-nut to stall zombies. However, you can still freeze them with Chilly Pepper because it is an explosive plant.