Ice Station

Ice Station is the eighth  mission in. It is unlocked at level 14 and is 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 HVM Soldiers who turn against the player(s) after the first wave of zombies, a truck which will transport the player(s) after a certain point, and two guaranteed strongbox drops from HVM Captain and the boss as well.

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/she can.

Layout
Players spawn nearby a truck in a closed-in station with barricades, similar to a level in SAS: Zombie Assault 3. The HVM Captain and his soldiers are also 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. Despite there being several barricades to defend, the HVM soldiers and the captain himself are also there to help. 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), the player(s) can fix it, either partially or entirely depending on if the player(s) leave the barricade before the repair animation finishes.

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 weapons they were shooting at the zombies earlier are being fired at the player(s), damaging them if they get hit. 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. The objective of the mission changes to 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 player(s) have to kill zombies that try to swarm the truck he/she/they is traveling in. The truck takes damage from zombie attacks.

Along the path the truck takes, there are several snow-covered boxes that players can shoot for loot drops. The truck also goes through many obstacles, such as barricades that need to be shot down. The unnamed driver is implied to have been killed by an avalanche that destroys the truck. After the avalanche, the player is bought to an area where there is a boss zombie. After clearing all zombies in the area, the player wins.

Tactics

 * During the part where zombies swarm the station, it's usually not a good idea to stay in the upper or lower right corners of the map because if zombies break down the other barricades there is a good chance you will get swarmed and killed.
 * Stay around the truck and defend the two gates top and bottom.  The zombies from the other end of the map will be drawn to the HVM mercs first and not make it to you. This will mop up most of the zombies before they reach you.  Drop a turret near the back end of the truck and you should be good.
 * LMGs are good for the part with the truck, as they are quite powerful and movement isn't important. Shotguns also work well, as they devastate at close range. Rocket Launchers excel against shielders, and thus they are 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.
 * During the boss fight, the method of running in circles and shooting will not work because bullets from the player cannot penetrate the center column of snow.
 * Stay in tight to the central column and remember that the bosses are at their most vulnerable when they are slowing to turn a corner.  The tighter you are in the middle, the more turns they have to make.  If you get pushed out into the open by the smaller zombies, the bosses have the advantage and can run you down.  Drop turrets in the corners where they have the longest periods to fire at the bosses as they slow to turn.  Get the small mobs to follow you and drop grenades as you run around the center.

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 opponents.
 * 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.
 * 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 box from the HVM captain: 1 in the bottom right room, 1 under the ambulance and 1 in the truck.

Map Specific Achievements

 * Mechanic
 * III Be the Action Hero
 * Map Champion - Ice Station