This is Defenda! by Johnathan Sole, from 1991

You pilot a Ship, and you need to destroy all the Aliens which will kill you on touch

You must defend the Humans standing on the Planet surface from these Aliens who will swoop down and take them away

Dotted around are Volcanos and Mines which should be avoided as these are deadly to the touch

Asteroids will also appear which when shot will reveal a bonus bubble which you can collect which can give you an Extra Life, Extra Smart Bomb, Mace, Extra Speed or 1000 points

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Code: Jonathan Sole