Turn the brightness up
Stay in the middle most of them on the sides actually miss.
Use both guns to blow them up faster especially some of the big ones look like small ones.
Its really luck based you could have 3 big ones go right above you and bring you down to like 55% hull or you could have all of the big ones going down the center. All in all keep trying and you will get it.
Thanks to Magixman for the sig!