ARCADE GAME SERIES: GALAGA

Right after level 18 you will encounter another Challenging Stage. Immediately into the stage you will see a large wave of Mosquitos and your achievement will pop. You don't need to kill the you just need to see it.

Tips to make the game easier:
Before the game starts you can go into Settings then Game Settings and change your maximum amount of lives from 3 to 5. You can also turn on select level. This will allow you to choose any level that you have reached. I would also recommend holding down the button instead of pressing the button because it shoots faster.

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