MegaBattle is an action game that pits one or two players against oncoming hordes of bad guys. Since their only goal is to destroy, players have a moral obligation to get them first.
Your only chance is to build a base, throw whatever you can find at them, and collect special weapons, which will give you that extra edge.
Press F1 while in the game to open the help file.
Press F2 to restart the action from Battle 1.
Press Escape to go back to the main menu.