A few years ago, the South Korean game developer COM2US successfully trademarked the term "Tower Defense" to protect the title of one of its popular games for the iPad / iPhone TowerDefense: Lost Earth.
As the term began to gain popularity, the trademark was granted. It was used, and is still being used, to describe the growing number of browser-based strategy games that are available online. Many websites that offer embedded Flash games and links on their sites use Tower Defense as a category. The COM2US video game is not usually found in this group. If you want to know more about the XNA game studio then you can visit at https://rocketbrush.com/.
Tower Defense (TD), is a game where the main objective is to stop an enemy from crossing a map. In the earliest types of TD games, the enemy was some type of medieval band of conquering soldiers, and the goal was accomplished by placing towers about the map or maze from which archers could launch arrows to stop the marauders.
As the enemies arrived in waves, the game player could increase the number of towers to help defend against the next wave. Game developers have become more creative over the years by changing the types of towers, enemies, maps, and mazes.
There are many upgrades available, including boomerang throwing monkeys and magic monkeys. You can also use spikes to defend the paths.