In year 2222, people invented a portal. In year 2281, the first habitable planet is found. Its colonization is made through portals and it turns out that humans are not the only sentient race in the universe..
Use towers to build a labyrinth from entrance to exit. Each tower can be upgraded 4 times. With each wave, enemies will become stronger, so use money you earned to upgrade reasonably.
One last turret stands between you and total annihilation. Destroy all malevolent alien ships by upgrading your cannon and building the ultimate killing device!
Fight against humanoid military forces through 6 different worlds, command allied troops armed with powerful lasers and destructive rays, upgrade your weapons, unlock electric mines and homing missiles and destroy everything in your path.