The map is based like Gmod: Elevator Source, in which everyone spawns in a room (in my case the 1st floor in an office building) and each player enters the elevator and the *game begins*. Each floor will be something different, some will be filled with zombies, others with boss zombies, some with no zombies just a perk machine/PaP, or a combination of both (NOTE: Players will not be able to exit the elevator on all floors, only those that have machines.). So as you go up the floors get more difficult. and once you make it to the roof you hold off until help arrives, or you just buy the end game.

-Make the game start ONCE the elevator starts going up.
-All players must be in to get the elevator going
-Elevator stops at each for a certain amount of time
-Add music to the elevator
-Adding Bosses (Witches,Warden,Napalm Zombie)
-AND A FEW OTHERS (i cant think off the top of my head but minor stuff)