Just came across this over on DeviantArt. PURE GOLD:

Left4Dead – Aperture Science by ~FireOps on deviantART

Why has no-one thought of this before now? Ok, the chances are someone has, but why did no-one tell me?! The whole secret-underground-research-facility setting is begging for a zombie revamp but neither of the Resident Evil mods that I’m currently aware of (here and here) deal with the Umbrella Corp’s lab beneath Raccoon City.

Clearly any campaign set in Aperture’s labs would lack the portal gun itself (we’ll just have to hope for multiplayer in Portal 2), but there is ample room for exploration of other areas in the Aperture complex. I see a potential campaign being executed in one of the following ways:

1. The players are the survivors of an experiment-gone-wrong in the Aperture labs and must escape to the surface. This option is too much like the Resident Evil option for my liking.
2. The survivors are part of an experiment involving huge numbers of zombies controlled by an Artificial Intelligence that actually exists in game. They are put through a series of ‘tests’ (chapters) and eventually find a way to escape their confines and destroy the A.I. in the finale.

I’ll repeat the last point in case you missed it: You get to kill the A.I. Director. How rewarding would it be to dispose not only of the mastermind behind your imprisonment in the Aperture labs, but also a personification of the entity responsible for killing you in every single L4D game you ever played?

I really hope there is a mapper or modder with enough free time out there capable of taking this on. I really do. So hurry up Valve, release the L4D SDK already so that someone with talent and time can implement my dreams.