Tower defense

A sub-genre of strategy, tower defense games are categorized by the management of a line of defense which should be able combat and defeat incoming enemies. The main objective is to avoid enemies from reaching a certain location in the map. The enemies usually march in waves, following a determined path in an area or maze, in which the player arrange their units of defense, denominated towers. Such games can have stats and upgrade options, making it possible for the player to fortify its line of defense and implement more towers, as the waves of enemies tend to get tougher for each new level. Some games may even allow the player to decide the start of the next enemy wave, so they can take their own time to prepare and revise a strategy. If the player fails at defending the locations, allowing the enemies to reach them, it could either mean immediate defeat or attribution of points of damage which result in a defeat after reaching a determined amount.

The first recognized tower defense game is Rampart, released in 1990. The genre would become more known in the later 2000s with the release of several games, such as Plants vs. Zombies, Bloons Tower Defense 5, Lock's Quest and Flash Element TD.