Tanks But No Tanks

You must defend the last free outpost. If it is destroyed, the free world is doomed. In Tanks But No Tanks, you are a lone tank defending your outpost against waves of phantom tanks. These tanks appear and disappear on the screen. There is a total of twenty phantom tanks per level, although not all are on the screen at one time. Once all twenty phantom tanks are destroyed, you move to the next level. In level one, you have a wall maze to slow the enemy. In level two, you just have a small island as a shield. In level three, it's you, your base and the enemy, nothing else. You have five tanks per level. If all your tanks or your base are destroyed, the game is over.