Bloons tower defense 4 (BTD4) is one of the best and addictive game ever produced. Its high quality graphics, fascinating and entertaining music will keep you glued for hours. BTD4 comes with the same concept as in the previous games of bloons tower defense series. You have to build defensive towers and have to stop the enemy bloons from crossing the map. If 100 balloons cross the map you will lose the game. The game contains several new towers and more advanced tracks. You can upgrade you weapons upto two levels to improve your defense. Dart monkey can be upgraded to boomerang monkey and super monkey which will allow you to pop more bloons in a single shot. The game contains six different tracks to choose from. Bloons strength vary with colors. For instance, blue bloons require 2 hits to pop while red bloons are weaker and can be popped with just one hit. The game appears slow in the begininng as there are very few bloons. However as you proceed more bloons with faster speed and strength will come and make your life difficult if you dont have proper defense in place. YOu can use water and air defense against fast moving bloons. Overall the game is addictive and very challenging and will keep you glued for hours. Have fun!