Zombies
Have no idea but parts of this remind me of the first Resident Evil game a lot since I recognize a few sounds here from songs in the original game too. The song kind of makes you feel like you need to be very cautious as you keep moving forward in the city now being over run by the zombies that simply want flesh.
Luckily you have modified your handguns with silencers so killing one will not garner you very much attention. As you walk by one street, you see your once best friend has become one of them feasting on the flesh of someone they recently chased down and ate.
You keep going forth hoping that you can escape the city before the night is over or simply hope this is all a bad dream. Having pinched yourself a few times you know this nightmare is real and indeed not just a bad dream at all. You keep pushing yourself to go forth, trying to find an exit to what feels like a doomed city wasteland.
The windy part of the song gives a feel of screams being carried through the air letting you know another person is dying. The ambient sounds hear give a feel of deep fear as you move along as well. The drums give the dynamic feel that there is terror behind every building and inside every building as well.
Overall, very well done song, almost sounds like something you would hear in a zombie horror survival game.