Tower Defense - 8

The goal in tower defense games is always the same: stop waves of enemies from reaching you. To do that, you place defenses in the best possible positions. Usually they're towers, but this strategy subgenre now comes in many flavors: heroes, traps, robots, and more. Plants vs. Zombies popularized the genre, but on Android, you'll find very different takes, such as Kingdom Rush or The Battle Cats.