Rumours about a new Left 4 Dead game have been circulating around parts of the internet for years. Turtle Rock and Valve’s quasi-AI directed games about killing zombies were an absolute blast to play co-operatively, and fans have been clamouring for a sequel. While games like World War Z have filled in that niche a little, they don’t quite compare to the thrills, spills and double kills from Left 4 Dead.