Plants Vs Zombies
This series of many games started years ago as one free online game of the same name. After it became extremely popular and successful, new versions of it were added, and they all tend to preserve the classic approach of castle defence games:
• Heroes
• GWT
• Garden Warfare
• Versions for mobile devices.

The castle defence is a type of free online games, in which there are enemies, who want to approach your castle (in this case – home) to destroy it and a player’s task is to build the line of defence to shoot at gradually approaching foes to kill them. Here shooters are plants of various forms and abilities and foes are zombies. Zombies may eat plants so beware!