Volfied

Once in the game, using the arrow keys you can move the 'Scanner' ship around the 'Shield Line' at the parameter of the playing area. While moving around this edge the ship is protected from the aliens by a shield indicated by a glowing circle around the ship.

This shield is not infinite and care should be taken to complete each level as quickly as possible. A counter indicates the level of shield that you have: when it reaches zero then any contact with an alien is deadly whether you are on the 'Shield Line' or not.