Another thing that was suggested by @Felipegames2000 was to have add another mode called Boss Hunt where players can use treats to attract plant & zombie bosses almost like a bounty hunter. There could be a sign in the backyard with a list of bosses to defeat and how much reward money you get from them depending on the difficulty (easy, normal, hard, or CRRRAAAAZZZZZYY). For higher difficulties, you may be required to defeat a certain number of bosses or defeat them using a certain character or variant (such as the ice cactus, hockey star, golf ball star, electro brainz, etc.).
