Object: to win the most points by using your Defender ships to protect humanoids from waves of aliens.A set of chance cards will bring the different aliens (bombers, landers and humanoids) into play. Movement is determined with a spinner. Players can move their defenders and aliens.From MNG-AJM Games Catalog: Board game based on the 1980's arcade game of the same name. Both players control Defender ships which have to protect Earth from alien landers which seek to abduct humans and turn them into mutants which return to attack the Defenders. A spinner is used each turn to decide what type of move you must make, but in each case you can make use of the move to benefit yourself or hinder your opponent. Interestingly the game ends only when one player has lost all 6 of his Defenders, and the player with most points wins, which may not be the player who still has Defenders left. - BoardGameGeek