This game may be the most out-standing hard-core game that you ever played, with the most suitable and the simplest control for a mobile game, you can draw any line as your shield on the screen with only one finger, go and clear those stages.
You should have no fear, although your tourism spaceship only equipped a defensive shield:
Unlocking every weird spaceship, learning unique character skills, collecting various gears, finding out your favourite best match, rebounding all attacks from the enemies! Having the strongest, the most absolute defense force, you would not need any weapons, because defense is the best attack! Get over the assault from the defense force, and enjoy your trip on the Earth.