This is the first set of levels, there are 25 to battle your way through here. The difficulty level is not very hard, the game rates it as 2 out of 5 levels.
But if you have only just started playing the game you may not have too many plants to choose from so that will hinder your ability to easily complete these initial levels.
Here is the list of plants that you will unlock in this world and a short description of what we think of each one.
Cabbage-pult - Level 2
Pretty useful as you first start in the game, but in the grand scheme of things it's really not that powerful! So use it one these initial levels as it provides a great long range attack but you'll soon be unlocking bigger and badder plants.
Bloomerang - Level 4
Handy but relatively expensive. Useful against groups of marauding zombies as it will damage three zombies in the same lane each time the a boomerang is thrown.
Iceberg Lettuce - Level 6
This one costs zero sun to use and it's really useful when you need a bit more time as it will freeze one zombie on the spot as soon as he treads on it. Works on one zombie only, then you'll have to replant once it has recharged.
Grave Buster - Level 9
Only really useful in this world - But it is really useful! As it smashes a grave that may be blocking your long distance plants from hitting zombies which are further back. An essential plant for many of the levels in this world.
Bonk Choy - Level 14
This is one of my all-time favourite and most used plants. I probably pick this plant in virtually every level. Boring I know - but it is just soooooo good - especially behind a blocking nut.
Repeater - Level 20
Just like the original pea shooter that we know and love, just this one fires two peas at a time - so double the strength overall - but at double the price.
Twin Sunflower - Level 25
When you are a bit tight on squares, this plant is a really useful one do have. Proportionally it costs a bit more than the single sunflower but at least you would utilise less squares overall, leaving more spaces free for attacking plants.