Nightmare Mode (SAS4)

"For the game mode of the same name on SAS 3, see Nightmare Mode (SAS3)."

Nightmare Mode is a multiplayer-exclusive mode introduced to around the beginning of February 2015. It costs one Nightmare ticket to play. You have five tickets per day, which are replenished everyday at 0:00 server time, which is UTC. There are also Premium Tickets which can either be bought with the Nightmare Veteran's Pack or after you run out of Daily tickets. Unlike regular Daily tickets, Premium tickets never expire.

Zombies are much tougher, and each map is individually redesigned. In addition, Nightmarish zombies exist, which are much larger than normal, and have the Nightmarish buff, which heavily increases their health, size, and damage, as well as 75% resistances to all types of damage. (They also have red labels when moused over.) Even a group of players at lower levels may meet bosses such as Nightmarish Savage Devastators or a swarm of Nightmarish Elite Necrosis, which can often lead to the death of lower leveled levels due to them not having tough enough equipment due to their levels and due to the bosses having all these Nightmarish buffs.

Nightmarish zombies have 10x health and 10x damage, are larger than normal, and have the following buffs: As you can see, these zombies have all of the resistances. All of the buffs on a regular Nightmarish zombie are listed to refresh your memory. This fact makes having at least level 8 Adaptive on your weapons, regardless of their damage type, a must if you are to play nightmare mode without spending extreme amounts of time on a nightmare zombie. Deadly and Overclocked are equally important, so don't forget those, either.
 * Nightmarish (1.5x size, 10x health and 10x damage)
 * Fiery Skin (75% resistance to damage)
 * Poisoned Limbs (75% resistance to damage)
 * Chitinous Hide (75% resistance to damage)
 * Energy Resilient (75% resistance to and  damage)
 * Extra Fast (50% faster movement speed)
 * Berserk (Triple attack rate)
 * Extra Strong (Double damage)
 * Ignoring armor (Since the 30th June 2015 update, all nightmarish zombies, including bosses, ignore 5% of the players' armors. Later, non-boss nightmarish zombies only pierce 3% of your armor)

Nightmarish enemies, however, do not come with Regenerating, Dark Minion, or Acid Blood. Nightmarish bosses can only come with Dark Minion, Extra Strong, Berserk, or Extra Fast, like with regular bosses, but they lack the 10x health, 10x damage boost, and multiple resistance like regular Nightmarish zombies do. They do have a massive damage boost, however, with even a Savage Regurgitator being able to one hit stronger players.

Every time a boss fight is won, one Savage boss that is defeated will drop five SAS4 cash packs and three strongboxes. The amount of the cash depends on how difficult the boss was. Nightmarish Savage Regurgitators will drop no more than $10k per stack while Nightmare Savage Necrosis will drop no less than $100k per cash stack. All regular bosses killed won't drop massive loots, but they will drop a single low quality strongbox or cash pack depending on the player's rank rather than the boss' difficulty. Since the October 5th update, all Nightmarish bosses will also drop alloy, with the amount depending on the boss difficulty.

Initially in mobile, anything savage would drop 3-4 cash drops and a strongbox, particularly savage Z-Droids, making Power Out and VIP incredibly overpowered, allowing for 30+ boxes in a single game. This however, has been patched.

Boss Spawns
Nightmare will spawn extra bosses in the middle of the mission, as well as at the end as usual. Boss type is determined by roughly total player levels*2
 * Onslaught: At 3:10 and 0:30 on the countdown. The boss(es) at 3:10 comes from the middle of the upper wall of the ship.On mobile bosses spawn at 2:20 and 0:30.
 * Vaccine: The train platform and regular boss area.
 * Survivors: The midway point heading north and regular boss area.
 * Zombie Pods: Aisle 2 close to the first purge nest and the boss egg in the regular boss area.
 * VIP: First opened room, and second is the regular Zombdroid spawns after setting foot on the south pad, whereas setting foot onto the north pad will activate the bosses from the south area. (Note: either pads can be activated, but the north side must be to finish the game).
 * Power Out: After flipping the first switch (spawn from right wall in main hall) and the final boss fight - which will always be a Savage Mech.
 * Last Stand: During waves 4 and 8. Waves will not progress past wave 4 until the boss is killed.
 * Ice Station: Right before entering the truck and the final boss fight.
 * Meltdown: When you enter the first reactor room, or by bumping the door to the right side of the room above (if entered via a different path). The second boss fight as normal after resetting the computer.

Overview

 * High Roller: If you are paired with high level players or with players that are generally your level and it is an easy map, use High Roller because there is a high chance you will win that map. It is advisable to get High Roller mid-game when you see what type of boss is there; don't get it when there is no savage boss, or a horde of weaker savage bosses such as Regurgitators. One bad box or even nothing is not worth it.
 * Even a group of players at intermediate levels may meet bosses such as a Nightmarish Savage Devastators (they start appearing at around level 50) or a swarm of Nightmarish Regurgitators. Unfortunately, all it takes is just ONE level 90 or higher player to give a high chance of a Savage Necrosis spawning in this gameplay mode. It can also occur with a team of level 60, 70, and 80 players.
 * To encounter the hardest Nightmarish enemy, Nightmarish Savage Necrosis Elite, it requires a minimum of 396 sum level of the players in the lobby (e.g. 4 players with level 99). However, the appearance of a Savage Necro Elite is still uncertain regardless of the chosen map.
 * Despite having a level 400 NM game (4 level 100 players) there is still a considerable chance of getting a group of Savage Wickers and Savage Regurgitators as mid- and end-bosses.
 * Even a Nightmarish Bloater Worm is no laughing matter. Worms and Puke worms with the extra fast or extra strong buffs can still be deadly due to the massive health boost of all Nightmarish zombies (bosses excluded), and they can sometimes take out the whole team with relatively little effort and with surprising quickness. Be prepared when opening the small pod eggs, especially in the secret room after the last and 5th purge nest in Pods.
 * In Pods, there is a fifth purge nest to kill before the gate opens. This nest is located where a medkit spawns in regular modes. Also, in Last Stand, there is a nest in the bottom-left corner of the entire map, which will spawn zombies that go directly to the exit. Kill this ASAP, before the nest's zombies kill all civilians. Another purge nest is in the final boss area of the map Survivors. It's located behind the destroyed truck in the right part of the boss area. If not destroyed fast enough, this nest can easily take out your team with its spawns.
 * When playing VIP, the VIP generally appears much earlier than normal, and also has more health to compensate for the zombies, making his health scale roughly on par with normal.
 * Since Nightmarish zombies have resistance to all damage types, a weapon with a good level of adaptive augment is helpful in this mode, due to the fact it reduces resistances by up to 40% (at augment level 10) or 50% if EACs are used (at augment level 12).
 * If you are a medic, use Biocleanse Bomb as much as possible as it will lower the zombies' resistances even more (along with the usual medkit).
 * Rocket launchers/LMGs/Flamethrowers are also useful as they add another 25%/35%/25% to the resistance reduction if the fifth/fourth mastery is achieved, respectively. If a player has 12 adaptive and rocket launcher mastery level 5, there will be a 75% damage resistance reduction rather than 50%.
 * On the note of adaptive, a 10 adaptive lvl 5 mastery on an LMG will provide 75% resistance, without coring.
 * However, deadly (tenacious if it's a stripper or flamethrower) and overclocked are still more important than adaptive.
 * This mode used to have no level selection, meaning that anyone could be in your team, but now in the May 7th Update, level selection was added and you would now get players near your level. After another update, players may choose to play with similar level players, or players of random levels (above 35, of course).
 * After the June 30th update, the host of the match is now allowed to select the mission they want to play in Nightmare.
 * On 11/18/2015, Ninja Kiwi had released Nightmare Mode to the mobile version of SAS Zombie Assault 4, but only on Android.
 * On 11/20/2015, Nightmare was released on iOS.
 * On mobile, Zombdroid Servants and Zombdroid Soldiers are capable of spawning with the Nightmarish modifier.
 * Bosses on the mobile version do not always come with the Nightmarish modifier.
 * In Pods, every minion egg used to spawn a single Nightmarish boss along with the regular boss spawn from the boss egg, making the level extremely difficult. Pods has since been changed back to spawning bosses only from the boss egg and the midway spawn.
 * Recently, Rohan added a new update involving a new Level range: Public-99-100 (as it totals 396 or higher).
 * On 3/24/16, an update added Nightmare private matches for mobile.