Chalgyr's Game Room writes:
The Tower Defense genre has been a popular format, typically found in Flash or other web-based games. Usually adhering to a top-down format of placing defenses at static locations in order to protect against waves of enemies, it lends itself well to short pick-up-and-play sessions. While there have been some standout releases like Defense Grid and Anamoly that have come out on Steam, most other releases have felt like ports of existing web or mobile games. In order to bring a more robust and unique experience to gamers, the Action Tower Defense genre was born. Putting the player in charge of an avatar inside the game world, and allowing for more customization and direct interaction with the enemies and surroundings, games like Sanctum and Orcs Must Die have created a completely new experience. Dungeon Defenders from Trendy Entertainment was among the first wave of entries in the genre, and their follow up game Dungeon Defenders Eternity has just been released.