Tanks But No Tanks

Defend the last free outpost from destruction, for if it falls, the world will be lost.

The levels become increasingly difficult: in level one, you must navigate through a wall maze to slow down the enemy; in level two, it's just a small island to protect yourself; and by level three, it's just you, your base, and the enemy. You start with five tanks per level, but if any are destroyed or your base is breached, the game is over.