The Wild West is another crazy world, this time you are introduced to sliding carts which are really handy to cover multiple lanes with a single powerful attacking plant.
Look out also for the guy playing the piano which allows the zombies to change lanes - nightmare.
Here is a rundown of the plants unlocked in this world.
Split Pea - Level 2
A peashooter which is able to shoot a pea both forwards and backwards, especially useful when a zombie has flown past you and landed or when a zombie has changed lanes. In the wild west, this is a particularly useful plant.
Chili Bean - Level 5
Plant this bad boy and the next zombie which lands on it and eats it will fart sooo bad he'll die. Handy little plant when you are a little stuck. Hit it with a leaf and it will multiply.
Pea Pod - Level 7
This is for me the best pea type plant as you can plant multiple pea pods on the same square - up to five. So five shots will be fired per recharge. Or course this costs quite bit, but really useful in the longer levels where you need to build up some strength.
Lightning Reed - Level 10
This sharp shooter hits zombies in it's own lane and the lanes one above and one below. Really useful for some of the wild west levels when placed in a cart. Not so strong but covers a large area well.
Melon-pult - Level 13
Expensive but large damage plant especially when you power it up with a leaf. Really useful, especially if you can get a whole column of these. The leaf effect is really good too, hitting multiple enemies in multiple lanes.
Tall-nut - Level 19
Just like the wall-nut but a little bit taller so it will block low-flying zombies. They are quite a bit more expensive than the standard wall-nut so take a sneaky look at the enemy before you start the round to decide whether you want to get the tall nut or not.
Winter Melon - Level 25
A bit like the melon-pult but a bit better as any zombies that are left over after being hit get slowed down too. But quite a bit more expensive than the melon-pult.