If you fly into the first end of baddie when its jaws open up while avoiding its fire and being careful not to touch it, you will be presented with a version of Space Invaders. Complete one wave and you will be given three extra lives and be thrown back into the fray.

When you die, pilot your flashing ship down below the score at the bottom of the screen to have a free tunnel of aliens.

On the end of level 2 Guardian, be sure you have a couple of homing missiles and the side shot. As soon as the guardian appears, move to the top right hand corner of the screen and stay there. Keep your finger on the 'Fire' button until the guardian fizzles out and dies.