About writes: "Tower defense games have been growing in popularity at a rapid rate ever since the success of Flash Element Tower Defense and Desktop Tower Defense in 2007. Of course, the basic concept for these games goes back much further than that, bearing many similarities to old arcade games and mods made for StarCraft. Essentially, you have to destroy multiple waves of oncoming hostiles (creeps) by placing defensive towers on the map. These towers can typically be upgraded and in some games, used to force the enemy to take a longer path. Here are my favorite free browser-based tower defense games."