Hey, what's with the enemy soldiers wriggling and convulsing around after death, its like something out of a horror movie, and damn scary lol

I was doing kill tally on the streets and I plotted up inside a room in a dark corner and was picking the enemy off with the sniper and trip mines, and I had about 5 dead enemies in a pile doing what looked like a dawn of the dead break-dance ffs

FREAKY