Plants vs. Zombies: The Ultimate Adventure

This is a game by AllanTech.

Story
Crazy Dave decides to go back in time to change history so zombies don't exist, but accidentally causes the zombies to rule the world. So, the plants have to overthrow the zombies and restore order to Earth.

Story Set
Each world has 12 days.
 * 1) The Homefront
 * 2) Into the Jungle
 * 3) Dry as a Desert
 * 4) Riverbend
 * 5) West Zombie Homefront
 * 6) East Zombie Homefront
 * 7) Central Zombie Homefront
 * 8) The Final Battle

Bonus Set (costs $1.99)
Each world has 14 days.
 * 1) Take to the Skies
 * 2) Dark Forest

Golden Leaves
G-1: found by killing the third buckethead with a Snow Pea in The Homefront - Day 3.

G-2: found by using Power Zap on a Soldier Zombie in Riverbend - Day 7

G-3: to be added

Into the Jungle
to be added