As... IDK, screw the intro. Lets just get into plants etc.
For the main mechanic, every day would have a different mechanic. For example, a romantic show/day would have romantic heart tiles which heal plants/zombies on them. Also, some zombies are more likely appear in different days. Also, some days can have multiple genres. Do we need an example for that? This would compliment the idea of this world having the most zombies, though...
So, for our first (and currently only) plant (aka this thing:), it would have something to do with spotlights scare zombies away due to stage fright. Or maybe different colours = different effects. Please, I haven't decided yet! Maybe this pea which I'm calling "Agilipea" () could make it's debut in this world. It would speed up every plant on the lawn, and sometimes speed up zombies too. Some quick trivia = it would be the only pea in this game which wouldn't be a peashooter variant.
Anyways, now for the zombies. The basic variants would be: Actor Zombie, Baghead Actor (http://pvzcc.wikia.com/wiki/Baghead_Zombie), Conehead Actor, Buckethead Actor, Actor Flag Zombie, Tragedy Imp and Comedy Gargantuar. Well, I wouldn't say that the last two are just reskins for the world. Tragedy Imp would be scared of the Comedy Gargantuar, therefore it would be faster around them. They would also be too scared to be thrown, but would be forced anyways, therefore they would be quivering in fear when it lands for the first few seconds after landing. They will ALWAYS be faster on rows with Comedy Gargantuars if they're in front of the Gargantuar.NOTE: If we add world seed packets, I made one for this.