(Crazy Dave appears)
Crazy Dave: Butter and spikes and everything nice.
Crazy Dave: That's what butter and spikes are made of.
Penny: That's hard to argue or agree with.
(Crazy Dave and Penny leave)
Since the player cannot pick his or her own plants here, they must use the given plants to kill the zombies.
Kernel-pult, although has the ability to stun zombies, its attack is quite weak, so it cannot deal with hordes of zombies quickly enough. But the player is given Cherry Bomb, one of the most powerful instant-kill plant in the game, so use it wisely.
Imp Cannons appear and are your biggest threat, since only the Kernel-pult and Spikeweed can attack it (or Cherry Bomb if it's in the second or fifth row). Plus, due to a big amount of health for a few Kernel-pults to handle, you might want to use Plant Food.
Remember to use Spikeweed to attack the zombies when some of your plants have been destroyed.