Meltdown

Meltdown is a mission that was added to on February 11, 2015. The map takes place on Boreas, where the Government says it lost communication with the nuclear power plant here, and it's time to check it out.

Walkthrough
In comparison to the earlier missions, Meltdown is overall a very difficult mission as you have to wander through small corridors with doors that open and close randomly depending on how many zombies are in that corridor or room at the time. Heavy yet powerful and long-lasting weapons such as LMGs and Flamethrowers, or fast-reloading low-cap weapons such as 1887 Shockfield are recommended for this mission as you are likely to get cornered many times trying to find the reactors and during the boss fight. Some weapons with specialties such as Shredder, as it will bounce many times on wall to hit enemy multiple times if shot at right angle, and arc weapons, as the doors can be shot at and arc to the other side, will also work very well. Semi-automatic weapons and slower firing ones such as sniper rifles and pistols will most likely result in the player being overwhelmed by a horde and killed.

Adding to the difficulty, you are given only five minutes to find each of the three reactors AND shut them down, as well as having to move quickly through rooms that will fill with radioactive gas. Additionally, you should avoid the green medkits located near the reactors, as they deal massive damage to the player if picked up. After this, you must return to the computer and restart the power plant, which will also trigger the boss fight in the process.

The best way to avoid the gas rooms is to pay attention to the doors. Gas room doors will close frequently in an attempt to trap players. Exit those rooms as soon as you notice them before the doors can shut on you, and find another way around.

In the end, a large number of bosses may spawn, such as a Devastator, Wicker, and multiple Regurgitators. To have the best chance at winning the boss fight, it is recommended you circle the building and mow down the horde plus any weaker bosses that may appear (such as Regurgitators) before focusing on the stronger ones.

Tactics

 * Rushing can be helpful for this mission. It is advised to go through as many rooms as possible to get to the reactor room to shut it down, bringing fully-automatic rapid-fire weapons to take care of the zombies that will come through different rooms to attack you.
 * When you activate the main computer, immediately mow down the hordes that will spawn, and then circle the rooms, killing off the weaker bosses and leftover zombies. When this is done, target the stronger bosses and kill them off, and THEN celebrate your success.
 * When searching for the "Loot Cave" watch for holes where zombies do not come out, or are sucked back in.

Loot

 * In the gas chamber below the third reactor, there is a secret room with three hidden loots behind the bottom wall.
 * In all the reactor chambers there are lethal green medkits that will severely injure you if picked up. However, picking them up will cause your character to say some funny things, and nabbing all three of them will earn you the secret achievement Trying To Turn Superhero.
 * After activating all three Reactors, but before activating the main computer, the player can enter a hole (by walking over it) to be taken to a secret cave. These holes are what the zombies emerge from when a player enters a room, the correct hole seems to be randomized each time, and usually is not present at all. When all the zombies in the cave are dead, a lot of loot will come up. The cave can only be found over particular holes which spawn mobs for multiple rooms, if it spawns before you enter the room it's in, the cave will not work and cannot be found that game.
 * The secret cave apparently has an objective, saying "Prepare to Die." You most likely will be swarmed by zombies.
 * There is also a third secret room in this map that spawns loot for you at only specific occasion, where player only opens the 1st room, the corridor right under, then the room to right, which has a lot of boxes, but this time it will drop 2 loots with a medkit.

Map-Specific Achievements

 * Meltdown Countdown
 * Trying To Turn Superhero
 * Map Champion - Meltdown