Onslaught 2 - Features weapons such as rockets, lasers, turrets, and tazers with multiple upgrades and modification towers. Weapons can combine to form unique & powerful combos. Multiple course configurations. By Gaby Vanhegan.
Bloons 3 by NinjaKiwi.com. Bloons 3 is an extremely fun tower defense game by where you pop balloons by placing monkeys with a variety of skills and other weapons along a variety of different courses.
Pirate Defense by Hero Interactive. Create a course full of traps to keep pirates from reaching your booty! A rather unique feature of this game is how the mechanics of the traps allow you to string them together into combos that push the pirates back into traps that they've already crossed. Utilizing combos provides you with gold bonuses that allow you to upgrade and place extra traps. Bonus levels available at Armor Games.
Tower Defence by Roman Sanine. Source: onemorelevel.com.