Always a fan favorite, Call of Duty’s zombie mode made yet another return with Advanced Warfare’s entry into the long running franchise. Making its debut in the otherwise forgettable World at War, Call of Duty zombies have since been a staple in the series. Millions buy the game just for the chance to take on the army of the undead --hell, it’s the only reason I bought Black Ops. 

But before you jump in there are a few things you need to know. In case you have been living under a rock for the past decade, or just want a refresher course, here is a list of ten important things you should know before going into the game mode. 

10. What is the storyline?

The storyline is pretty simple – there practically isn't one. Many gamers are even surprised to find that the mode contains a story at all. Gameplay is king, and Activision knows it. Instead of bogging the game mode down with needless exposition or cut scenes, the developers let the gamers craft their own adventures through the frantic and explosive gameplay. I suppose there is some hidden information scattered around the maps and doled out through the occasional voiceover, but it’s not enough to distract from the main objective of the game mode… shooting zombies in the face.

For those truely intrested in the lore of Call of Duty's zombie mode there exists a story hidden throughout each map which reveals the origins of the zombie plague. For those interested here is quick passage that will get you up to date, but you aren't missing much if you don't pay it mind. In the end, the most important stories created from Call of Duty’s zombie mode are the ones you and your friends make. Those nail biting escapes, tough defeats, and close calls live longer in your memory than even some of the actual campaign modes.

9. Who are the heroes?

The heroes vary across each entry of the series. Call of Duty zombies absolutely oozes personality, and in few ways more than through its eclectic cast of characters.  As the game mode went along the characters quickly became more and more absurd. Generic American and German soldiers were replaced with the likes of John F. Kennedy, Fidel Castro, Robert McNamara, and Richard Nixon. Even the iconic Danny Trejo made a cameo appearance in the Call of Duty zombie mode. But in truth, the heroes are your friends and you. You are the only hope humanity has in surviving—for at least one more round that is.

8. What's the goal?

If you thought the story was simple, just wait until you learn what the objective is. It’s not to reach the end of the map or even to rescue a group of refugees. The goal is just to survive – or at least survive as long as you can. This round based game mode only advances after you kill every zombie, so it’s best to start shooting right away.

7. Why fans love it?

Let’s face it. We’ve all gotten tired of the generic Call of Duty formula at some point over the years. Every so often one of the games kind of just “happens.” (I’m looking at you Modern Warfare 3) With the breakneck pace that is Call of Duty’s release cycle it can be hard to keep interested in an old formula. As a result it takes something a little special to provide a shot of adrenaline into the series. Call of Duty zombies was that mode. Cooperative team play, mixed with tense, fast paced battles against the undead brought life back into the franchise – and each new release seems to bring something different. Black Ops brought new and exciting characters, while Advanced Warfare shook up the entire formula with the inclusion of the game’s new exo suit abilities.

6. What is the gameplay like?

Exactly as you would expect a Call of Duty game to be like—fast paced. Zombies do however start out slow. Don’t be fooled though, these lumbering goons are soon replaced with lightning quick versions of the undead. Similarly, difficulty scales with each increasing level. Zombies that could be felled with a few simple knife strikes soon require multiple shotgun blasts to take down. It’s a challenging combination, but one that leaves fans eager to try again after they inevitably die. There is some hope though; dozens of guns are available for purchase in order to combat the rising swarms of zombies. Pro tip: Only use your knife for the first few rounds. Try to save that precious ammunition for when it starts to get really challenging.

5. Enemies and Bosses

Zombies… next topic. Just kidding, the enemy types are constantly mixed up in order to keep the gameplay fresh and the players on their toes. Aside from the standard shambling grunts, expect to face off against the likes of space monkeys, zombie dogs, and, in a particularly clever homage to one of the genre’s founding fathers, the fearsome George A. Romero.

4. Maps

The levels are as varied as the cast of characters. Unpredictable locals are part of the draw of Call of Duty zombies. It’s always entertaining to see what maps the developers will cook up next. From swamps, to mountains, and even Shangri-La, never expect to get bored of the ever changing maps. My personal favorite however is the Moon level, which pits players against astronaut zombies and a variety of other space themed monsters. It was a truly unique level, and a nice change of direction from the usual style of maps.

3. What weapons do players get?

This is where the game gets interesting. Weapons range from your standard fare of World War II rifles, shotguns, and pistols, to the more modern weapons, and even the futuristic “ray gun”. But you can’t just rely on guns to survive. Players will have to work together to fight off the endless undead swarm. As you might expect, your mind is your greatest weapon against these brainless monsters. You’ll need to outthink the zombies more often than you will outshoot them. If you are smart you can take advantage of the zombie’s lack of directional abilities and lead them straight into traps or even towards your well-armed friends.

2. Over 2.5 billion zombies have been killed.

What exactly do those numbers mean? Well for starters people hate zombies. But it also means the mode is hugely popular, so for any newcomers out there, finding people online to help you out shouldn’t be an issue. You don’t need to have friends with the game in order to take on the hoard of zombies. Undoubtedly those numbers will continue to rise over the next several months as more and more people are introduced to the mode. It almost makes you feel bad for the zombies… almost.  

1. How to download and play it

To date four Call of Duty titles contain a zombie mode—World at War, Black Ops, Black Ops 2, and most recently Advanced Warfare. It is important to note however that the zombie mode in Advanced Warfare must be unlocked through playing the exo-survival mode or through the purchase of DLC. You can’t go wrong with any of them, but I would personally recommend spending the extra money to get the mode for Advanced Warfare. The exo abilities dynamically change the way you normally play, and might be enough to attract those who became bored with the mode.

Those who find Call of Duty zombies, well, a little “brain dead” might want to check out Extinction mode found in Call of Duty: Ghosts. It’s a Left for Dead inspired mode which absolutely requires teamwork and communication—even more so than in the zombies. There’s a chance that zombies might have met their match if the developers decide to give the mode another chance in a future title. What is your favorite part of Call of Duty zombies? Any memorable stories you would wish to share? Please feel free to share your opinions in the comments.