SAS Zombie Assault Wiki

The Meltdown plant. Rooms with only red doors are ones that will fill with radioactive gas

Meltdown is a mission that was added to SAS: Zombie Assault 4 on February 11, 2015. It is the 9th mission, unlocked at level 14, and along the map Ice Station, is currently available only on the PC version. The map takes place on Boreas, where the Trans-Federation says they lost communication with the nuclear power plant here, and it's time to check it out and shut it down.


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 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 the 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 (and using the Die Another Day skill doesn't mitigate the effects of them either). 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 Regurgitator bosses. 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.


  • Rushing can be helpful for this mission. Be sure your teammates are on board before you start running fast. It is advised to go through as few 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 are being sucked back in.


The infamous cave

  • 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. Getting all will also make the character demand to have another player to control him.
  • 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. TIP: The Cave are only located when the zombies sucked back at the Hole or no zombies coming are out of the hole. 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 has an objective, saying "PREPARE TO DIE." You most likely will be swarmed by zombies and will probably get killed instantly if not paying attention.
  • 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.


  • In all the reactor chambers there are lethal green (radioactive) medkits that will severely injure you if picked up. However, picking them up will cause your character to say some funny things, one such line that even breaks the 4th wall. Walking over all three will earn you the secret achievement (Trying To Turn Superhero).
    • However, in order to collect them, you must already be injured - walking over with full HP will do nothing.
    • The amount of HP lost when collecting a radioactive medkit is the equivalent to that of what you would gain if you were to collect a normal medkit. This includes powerups that affect your total HP gain from medkits.
    • If you're severely injured, running over a radioactive medkit will not kill you, and will instead reduce you to 1HP, making you vulnerable to anything that touches you, even with max resists.
      • If you collect any more radioactive medkits on 1HP, you won't be killed and no message will appear. This is one way to avoid your self-conscious character to demand being played by someone else.
    • The Die Another Day skill has absolutely no affect in protecting you from these medkits. Collecting a radioactive medkit with DAD active will result in the same HP loss as not using DAD.
  • This map is not available for the mobile version of this game, it is only available on PC.
  • The spawns during the end boss fight will follow a specific pattern of zombie spawns. Runners and Shamblers will accompany the bosses, shortly followed by Spitters and Stalkers. These are followed by a wave of Bloaters, followed by a wave of Shielders and a wave of worms and Spitters again. The final wave consists of Bloaters and Runners again and after this, no more zombies will spawn.
    • In multiplayer, if a player decides to stay in the cave, the zombies from these waves that were to target this player upon spawning, will remain stuck in the spawn locations outside of each corner of the map. To attract these zombies away from the spawns (so you can kill them), walk near the corners, or wait for dark minions to kill the player hiding in the cave. If any loot drops for the player in the cave, the loot will float outside the map making it impossible to collect when they decide to exit.

Map-Specific Achievements

Main article: SAS: Zombie Assault 4 Achievements
  • Meltdown Countdown
  • Trying To Turn Superhero
  • Map Champion - Meltdown


SAS: Zombie Assault 4 Missions
Onslaught · Vaccine · Survivors · Zombie Pods · VIP · Power Out · Last Stand · Ice Station · Meltdown