For all strategy games and defense games addicts, Monsters TD will give you a hard time!
This Flash game released in 2012 is now converted with HTML5 technology which allow you to play it on mobile devices as well.

Protect the gate(s) to your kingdom from monsters trying to invade it by building defense towers capable of stopping them.
Buy and place the towers in the right places with the starting amount of money, increase their number and their performance over the course of the game. A guide is at your disposal to tell you the particularities of each tower, but also those of the monsters and the magic powers available.
After each level won, you will get points that can be used in Skills to improve the playing conditions.

And now it's up to you !