Collect enough energy to organize a mech army to repel the evil aliens. Weapons escalating there. The hidden Boss waiting for you to discover. 3 kinds of difficulties, as you choose. You must be a reasonable use of your energy, to deploy the appropriate weapons to repel wave after wave of enemy attack. Plants vs Zombies fans must not miss. Easiest to hardest difficulty of the game, constantly unlock new weapons, more powerful monster emerging. You can try a different style of play to finish the game. You can also try different difficulty levels. Do not hesitate, act now.