This is the 4th part of Strategy Defense game. Below is the list of previous parts:
Strategy Defense 1
Strategy Defense 2
Strategy Defense 3
This game is practically identical to the third part. You and your enemy have towers and need to defend them and to attack the enemy. You can build defensive towers or train offensive units. You decide where to invest more. The main difference between this game and the part 3 are new levels and a bit harder game play. You have several towers instead of one and can choose where to release your soldiers pressing Z-X-C keys.