From Gamertell:
"Dango has created and launched Battle Defenders, an interesting, free Facebook game that could interest a lot of gamers. Battle Defenders is a tower defense game, a strategy title where you must place units on a field to prevent enemies from proceeding down paths to your goal. However, there's a twist - you get to be a defender and an attacker."
This isn't even multiplayer. You just pick one of your friends to "fight" against. They are actually just a computer AI with your friend's name and picture. Beyond that, it is also a very bad TD game. Stupid Stupid Stupid.