Welcome now to a (new) Infection Survival map. This game is based off of a game that I helped make popular on Halo 2 that was played on Headlong. The base that all the humans spawn at is modeled after the building used in the game on Headlong. It has now been cheat-proofed compared to my several old versions, while this should be my final version (at least on Halo 3 or Sandbox). Now begins the story....

A UNSC Team of soldiers has been attacked by zombie creatures. They were driving down a tunnel, when they were attacked, and many were slaughtered. The vehicles have been made useless, and unusable. We now have to stay in an ancient building, and wait for Evac. They say it will arrive in 20 minutes, but I don't think we can last that long. We must try, but the zombies pop out of nowhere, and they seem to come from everywhere.
This is Sergeant Conner
If you're listening to this, you are the UNSC

Okay, not really, just wanted to throw in some Terminator jokes ^_^
So if you didn't understand that, here's a basic idea of the game:
Zombies spawn in the crypt. They wait a small amount of time before the door is opened and they are allowed to choose from 4 teleporters. Each teleporter takes them to a different place around the human-held base. One leads to a small building that has a teleporter to the Third Floor of the human-held base (Just as it was on Headlong).

Humans spawn on a broken bridge. Note that I wouldn't move when I spawn, as a giant block shortly blows up a warthog, usually killing lots of people. If you die, don't worry, you'll respawn in the building. Humans have to leave the bridge within a couple minutes, as killballs envelop the bridge, killing any cheating campers. Yes, the bridge is CHEATING, once the game starts. Why do you spawn and are already cheating? Because it makes it interesting don't bug me.
The humans spawn with Magnums and Energy Swords, the Alpha Zombie spawns with a Gravity Hammer and an Energy Sword, and Zombies spawn with only Energy Swords. Humans can pick up the scattered Rifles around, the map hosts a few battle rifles and carbines, but be careful with the ammo, there isn't much of it. Infected Zombies have Poor Camo also, so they're sometimes hard to spot.
So the humans have 20 minutes to survive, and then they get evaced...actually the game ends and you go on with your life. If you DO legitely survive 20 minutes, I want to see that video.

The building is constructed with 3 levels, one with a hallway on the side, one with deployable covers to help block doors and a lift that leads up to the level (usually used by zombies), and the top floor, which features a hole that can be used to see the rest of the floors, and leads to a balcony with a teleporter on it, that can be accessed by zombies from using the teleporter on the other building. One of the zombie spawn teleporters leads to that building.
Now for downloads. Lots of people dislike the camera effects, so you can get the version without it if you wish.
DOWNLOAD
20 Min 'Til Evac (Map)
20 Min 'Til Evac (Map without effects)
20 Min 'Til Evac (Gametype)

Strategies I've seen used:
1) The top floor has the least amount of doors. There are only 3 ways to get in, two being easy to see and block, and one that comes up below. There is a hole on the top floor for seeing onto the Second and First Floor, which is helpful for watching for zombies. This is possibly one of the best spots to hide, yet zombies can use the Gravity Hammer through the floor, so be careful.
2) The hallway on the First floor is a good spot, but presents a small amount of space. There are only two doors, but it may be hard to see if zombies come in, as they can pop in quickly.
3) The Balcony can be used well for hiding. Zombies can hit you if you're near the edge, so you need to be careful. There are 2 doors, and one teleporter to this area. You can block the teleporter easily with your body, and make it hard for zombies to enter, and easy to pick them off when they appear outside the zombie building.

And so the epic pictures begin...
I'm using the non-gloom version of the map so you can see details.

The main building that the Humans control

The Human's spawn. There should be a warthog under that floating block, don't understand why it didn't spawn in this picture, I'm sure you'll see it in-game :p.

Zombie controlled Teleporter building

Zombie Spawn area. Each corner has a teleporter leading to somewhere on the map.

First floor. Contains the stairs to the Second floor, and a hallway on the right.

Hallway area. Usually used by the zombies to enter the building.

Second Floor. Has access to the Third floor, access to the second is available for zombies from the lift around the corner. There are deployable covers on the blocks to use to block doors. Not as useful as the gigantic boxes used on Headlong, but it helps block doorways.

The Lift used by zombies to enter the building.

The Third Floor. Has access to the balcony, and has a hole that can be used to view the other 2 floors.

Another view of the Third Floor, showing off the small hallway in the middle, and a door leading out to the teleporter balcony.

For anyone who cares (most people usually don't) I spent many months working on this off and on, until it was ready for testing. It was thoroughly tested by several groups of friends, and was deemed pretty much cheat-proof, especially compared to my older versions.
The only cheating I can notice is that you can continually commit suicide, but most of the spawns are inside, so it's easy to catch cheaters. Also, the bridge is a pretty good cheat spot, but the killballs usually get rid of cheaters there. It shouldn't be possible to get on the roof, maybe only as a zombie.

Please post any (non-stupid) comments and concerns below. I'd like to make plenty more maps using this gametype, but I want this one perfect first. Been thinking of good ideas of what can be amazing for a survival for 20 minutes.