This is my rough outline for the Great Depression. Please give feedback to improve it.
Stock Market: The stock market affects plants, zombies and the sun in the Great Depression. It has three forms: stable, high and low. A chart in the background of the lawn indicates form it's in. The chart will be yellow when stable, red when low, and green when high. When stable, sun is worth 50, when low, sun is worth 25 and it falls less often, and when high, sun is worth 75 and falls much faster.
Pistachio: Acts like a sun bank. Click and hold to store sun. The longer it is held, the more sun is stored. Click again to release the sun for later use. It also has elevated toughness.
Parflip: Flips plants, making them attack backwards.
Trash Shroom: Lobs garbage at zombies. The garbage can vary in damage and can have various effects like stun or poison. When the stock market is low it fires faster, but when the stock market is high it fires slower.
Stock Shroom: Fires a stock arrow at zombies that changes depending on the stock market. When the stock market is stable it fires a yellow stock arrow that has a chance to generate coins off zombies. When the stock market is high, it shoots greent stock arrows which do less damage, but it fires them faster, and when the stock market is low, it fires red stock arrows that do high damage but it fires them slowly.
Cashew: Zombies that eat it generate coins upon taking damage. Generates more coins if the stock market is high and less coins if the stock market is low.
Grain Buster: Destroys a plant but refunds twice it's price back in sun.
Ragweed: Snares the first zombie that steps on it and causes the zombie to explode into a heap of coins, then it dissapears.
Polarugula: Freezes zombies in a 3x3 area and chills the rest of them. The fullscreen chill has a slight delay form the 3x3 freeze.
Bum Zombie: Has more speed when the stock market is low, has less speed when the stock market is high.
Conehead Bum Zombie: Has more speed when the stock market is low, has less speed when the stock market is high.
Buckethead Bum Zombie: Has more speed when the stock market is low, has less speed when the stock market is high.
Hoover Flag Zombie: Can summon Bum Zombies when the stock market is high, has reduced speed when the stock market is low.
Tramp Imp: Has more health and less speed when the stock market is high and more speed and less health when the stock market is low.
Great Depression Gargantuar: When the stock market is high he has an unlimited supply of Tramp Imps and will throw one every time he smashes a plant. He also has reduced speed. When the stock market is low he has increased speed and his smash has a 3x3 range. Only the smashed plant will be destroyed, surrounding plants just take damage.
Hobo Zombie: Slow, dumb and broke zombie. He pushes a oil barrel with a fire in it. If the stock market is high the barrel will shoot a fire ball in the air that will land on a random tile and damage plants. When the stock market is low, the barrel becomes an immobile tombstone and the Hobo Zombie gains the ability to push plants. When the stock market becomes high, barrels taht became tombstones will regain the ability to shoot fireballs and they can be pushed again.
Employer Zombie: Stationary zombie that hires bumb zombies and gives them a cooking job. Bum Zombies with jobs can throw pots and pans at plants. Hires less frequently when the stock market is high and more frequently when the stock market is low.
Bennet Buggy: Releases Tramp Imps upon being destoyed. When the stock market is stable it will be a regular car and move at a regular speed. It has a better engine when the stock market is high and is much faster. When the stock market is low, it is pulled by a horse and it is much slower. The horse isn't a zombie because he gallops off the lawn when the Bennet Buggy is destroyed.
Pickpocket Zombie: When the stock market is high they can switch lanes, but can't eat plants. When the stock market is low, they can walk backwards and can eat plants. He also can steal nearby sun.
Chef Zombie: Cooks food that heals zombie. Produces food more frequently if the stock market is low and less if they stock market is high.
Pigeon Keeper Zombie: Releases Zombie Pigeons when damaged.
Zombie Pigeons: Poops on plants stunning them for a bit, then flies away. Blover is their weakness.
Trash Can Zombie: Abosrbs lots of straight damage, but is vulnerbale to lobbed shot. When the trash can is destoyed, it releases a Tramp Imp.
Beggar Zombie: Steals sun to increase his speed. He is more aggressive when the stock market is low and more passive when it is high.
Umbrella Zombies: Falls into the heart of your defences. Moves faster when the stock market is low and slower when it is high.
Newspaper Bum Zombie: Speeds up when his newspaper is destroyed. When the stock market is high he will throw his paper straight at plants when it is destroyed and he will run slower. When the stock market is low he will put it over his head, giving him protection from lob shots, he runs faster when it is destroyed as well.