Martians

Martians is an action game with some similarities to Avalanche and Kaboom!. The player has to prevent aliens from landing and this is done by moving a force field left and right across the screen. There are three kinds of martians: invaders, destroyers and impostors. Invaders are stopped by catching them with the force field while destroyers have to be allowed to land or else they will destroy the force field and thereby end the game. Impostors are invaders but change into destroyers on their way down. The game is over when landed martians create a column of six aliens. For each invader caught with the force field, the player earns fifty points. When reaching a score of 10000 (and for every 5000 points after that) the player gets access to a bomb which can be used to destroy some of the martians. Before a game, the player can choose a difficulty level from one to six.