Yeah, yeah, I know this has been done before but I made a map anyway and thought I might show it to the willing and unwilling.

LEFT 4 HALO
"Fight 4 your friends! Fight 4 your life!"

The Goodies:

Somewhere in a sandy city, a zombie break-out occurs. No one really cares to do anything so the surviving spartans/elites must escape from their undead friends!

The Safe House isn't safe for long. Better get moving.

Move through the building. There is only one way to go!

The alley way is very dangerous. Watch out from zombies from behind, they will kill you in one hit!

This gate is locked to prevent the infection from spreading. Obviously, it didn't work.

The key is nearby inside a building. But who said getting in was going to be easy?

Moving along, the streets show the plight of people and the mess left behind.

While there are other alley ways with helpful tools, they are not the way, but will assist you to the key.

The entrance to the building for which you seek is at the end of the street. Wind through the building and you will get to the key.

Key in hand, you are able to go through the gate...

...only to find more ruin.

Certain, shotty, users may want to take a detour to a certain weapon.

At the end of the road (literally) you will make your last stand against the zombies. Beware, while it may look as if you can camp, they will come at you from everywhere if they're smart.

Points of Interest
Humans
-Their health does not regenerate. But is plenty.
-Start with pistols, but weapons with limited ammo are spread out through the level.
-Limited jump.
-Swords can be picked up as melee weapons, though it will ultimately drain your health and is not recommended.
Zombies
-Health is low, numbers and teamwork are key.
-Jumping is high. Use it for ambush!
-Swords are the weapons of choice in the afterlife. Who knew?
General
-There is a 5 minute time limit. That is when the 'copter comes and ends the round.
-Ammo does not respawn, except the pipe bombs (spikers) and molotovs (firebomb).
-50% of the players are humans and the other half zombies. If you so wish, you can adjust the zombie spawn to the current number of players minus 4. So if you have 16 people, set the zombie spawn to 12. Or if you have 9 set it to 5 and vice versa. This is only if you wish to get the original left 4 dead experience (results may vary).
-HIGHLY recommended to play with 10-16 players. Otherwise, it gets boring.

click -> GAMETYPES HERE! <- click
From what I've heard, people don't like this gametype. I think it works well. If you use your own gametype, make sure that humans have limited jumping, otherwise the map will not work.
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click -> MAPS HERE! <- click

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OK, nothing. Really? Any criticism will do.