Great job! Nobody needs L4D anymore. ;-)
Just one minor thing which makes me a bit unhappy:
In your OP you wrote 'many, many zombies'... "Yay!! Finally some real zombies and not these styleless infected!!":yay:
But there are no zombies (slow but sturdy, can only be killed by destroying the brain), you used infected (the 'modern' zombie: fast runner, goes down fast). :butbut:
Anyway, great fun to play, like L4D for adults.^^