If there’s anything that’s super awesome, it’s playing one game inside another game. Like playing Triple Triad in FFVII, or playing Left4Dead in Minecraft. I’m sure you’ve already inferred what’s going on simply by reading the title, but in the interests of absolute clarity, let me state this plainly. This is a survival map download in which the Left 4 Dead worlds have been paid homage to in the most ubiquitously blocky of ways. So you can play a zombie killing game whilst you kill zombies whilst you, er, zombie.