Ice Station

Ice Station is the eighth mission in. It is unlocked at level 13 and is currently only available in the PC version. The mission takes place on the icy planet Boreas, and it features unique game mechanics not seen in any other mission in SAS 4, such as Human enemies who turn against the player(s) after the waves of zombies, and two guaranteed strongbox drops (one from the HVM Captain and one from the boss).

Plot
The SAS has lost contact with the mining colony on Boreas. They suspect it may be infected, but they don't know how. By the time the player(s) are sent to Boreas, HVM has already sent a large group of mercenaries to assist local government there. It is the player's task to find out what he can.

Layout
Players spawn near a truck in a closed-in station with barricades, similar to levels in. The HVM Captain and his soldiers are nearby, waiting for the player(s) to approach. After the player(s) talk to the captain, he tells the player(s) to get to their stations to defend as zombies approach the station from the outside.

Similar to SAS 3, as long as the barricades (shown green on the minimap) aren't broken down, the player(s) are safe from zombies, with the exception of Dark Minions. There is a total of 8 barricades to defend, but the HVM soldiers and the captain himself will assist the player. Should the zombies damage or break down the barricades, the player(s) can repair them. By standing next to the broken barricade (no key-pressing is required, unlike SAS 3), the player(s) will automatically fix it, either partially or entirely depending on the time player(s) stand next to the the barricade. Barricades take a while to finish repairs compared to the instantly-repairing barricades of SAS 3.

After the wave of zombies stops, the HVM Captain and his soldiers gather around the ambulance in the station, which is presumably holding injured soldiers or citizens of Boreas. The captain then orders the soldiers to fire at the ambulance, and they do so. Once the ambulance is destroyed, they turn hostile to the player and attack him/her. The player(s) must subdue the HVM Captain and his soldiers in order to proceed with the mission. The HVM Captain, when killed, is guaranteed to drop a Strongbox.

Afterwards, the player boards a truck where the driver takes the player away from the Ice station. In Nightmare Mode, there are some Bosses in near at the transport truck. The player(s) must clear the bosses before going in the transport truck. The players must protect the transport truck. While inside the truck, the player(s) cannot move out of the truck, but they can shoot zombies from inside the truck. Zombies also cannot move inside the truck (unless the game glitches), again with the exception of Dark Minions. The truck takes damage from zombie attacks (see Ice Station Truck for more information).

The truck goes through several obstacles which the player can destroy by shooting at explosives nearby. At the end of the ride, there is an avalanche and the unnamed driver is implied to be killed. The truck is also destroyed. After the avalanche, the player is brought to an area where there is a boss zombie. By clearing all zombies in the area, the player wins.

Tactics

 * LMGs (like the Proposition and CM 530 BabyCOM) are good for the part with the truck, as they are quite powerful against crowds and movement isn't important. Shotguns also work well, as they devastate at close range. Rocket Launchers excel against Shielder zombies, and thus they are also good weapons to use on the truck, as Shielders can defend other zombies, and a large group of them swarms the truck at one point.
 * Spitters and Dark Minions are the only ones that can harm the player directly, and are more dangerous when the truck stops, so take them out quickly.
 * Use Cryo turrets in the truck phase, especially in Nightmare mode.
 * During the boss fight, the method of running in large circles and shooting will not work because bullets from the player cannot penetrate the center hill. Players will have to make smaller revolutions around the boss itself, which is riskier.
 * Or during the boss fight, if the boss isn't dark minion or extra fast, try backpedaling it and when it starts getting closer, equip your pistol, (if you have one), shoot it, face forward, run to a safe distance and resume pounding the boss. or have it travel in circles around your turret(s), but make sure it can't reach you!
 * Unlike the VIP, the NPCs do not receive scaled stats in Nightmare mode, making them essentially cannon fodder. Once they turn on the player(s), they can be easily defeated with a few shots each with minimal or no health loss to the player(s).

Trivia

 * This mission is the first mission that guarantees two strongbox drops; the first from the HVM commander, and the second from the boss.
 * It is also the first mission to feature human enemies.
 * This mission appears to be based or inspired by a thread post posted on the Kongregate forums created by a player. Similarities include requiring to defend doors or barricades, and a squad of NPC Humans led by a Captain or General.
 * Medics and Heavies may find this mission easier than the assault, as medics can heal themselves in the truck and heavies can tank the damage, whereas assaults have very limited room to run around in and dodge zombie attacks. However, Killing Spree is very effective on the truck.
 * Standing right up at the back of the truck, pointing your crosshair far outward, and throwing a turret will allow said turret to go out of the truck but still move with it.
 * This mission is placed in a completely different level list, more specifically, Boreas.
 * It is comparable to Zombie Pods, since both levels drop large amounts of loot.
 * Remember that at the end of the hospital section, there are three loot drops along with the strongbox from the HVM captain: one in the bottom right room, a medkit under the ambulance and one in the truck.
 * Ice-covered boxes along the truck ride have a large chance to contain loot as well.
 * An HVM Soldier will say two different things, depending on how well the player does at killing the zombies. Either "You aren't so tough" if the player doesn't do a good job at killing the zombies or "That's some badass shooting" for the opposite scenario.
 * The crates featured at the station itself resemble the crates on the craft on the map Onslaught, except these crates seem to be frozen over.
 * It's still unknown if HVM Captain & HVM Soldiers belongs to some evil organization or not.

Map Specific Achievements

 * Mechanic
 * I'll Be the Action Hero
 * Map Champion - Ice Station