This game is about defending your garden and not letting the zombies get into your house.
You can achieve that by planting a variety of plants that they have a defensive abillity and kill the zombies.
The main purpose of the game is to protect your house from the zombies by planting plants in different occasions like playing day,night(more difficult),in a swimming pool etc.
During the campain you will come across many minigames and you can collect money to buy other plants which are more strong that the others.
Here is a picture of all the zombies that you will meet.
Note:some zombies are harder to kill
A round goes like this:1)You have 6 slots to select your plants to play in this round(you can later unlock more slots), then you have some time to build your defensive lines against the zombies,after huge waves of zombies coming to invade your house :P
The main plants that you need at every game and round are
1:The sunflower=It is collecting sun and with sun you can grow faster other plants.
2:The peashooter=It shoots peas against the zombies and they are dying lol :P
Note*:After playing a lot of time you can find more shooters to kill zombies that are cheaper and more convenient to play.
All the plant seed packets that you can unlock during campain
Gameplay video:
This game was awarded as game of the year,its kinda funny to play but it gets a little boring sometimes
Download the trial here: http://www.popcap.com/games/mysterypi-vegas-heist?mid=mysterypi-vegas-heist_pc_en_full (the trial lets you play about 20 levels)
VIPS to download full version click here
Credits for the images to google and some of them from zombies vs plants wikia