The Wasteland

In 2021, a alarm goes off, A big item is visible in the sky, it's a circle and it's green, It hits the earth, killing everything and infecting everything into zombies with tan skin and bloodshot eyes, they eat anything in sight except themselves, You are a hazmat solider come to eliminate all infections, be whoever and whatever, but you need a gasmask, You have any gun you want and you have as much guns and as much ammo. You need NVGS.