Blockade Commander

A single player tower defense strategy. Defend your fortress and fend off the invaders. Place fortifications strategically, to ensure you repel the attackers from taking over your fort. Upgrade your fortifications and last as long as possible, or ascend to keep what you have and start again.
You will devise new strategies and obtain new units to defend your fort. Enemies will get progressively harder, increasing the challenge you have to overcome.