In the early rounds, before things get crazy, it pays to earn as many points as possible while defeating your foes. A melee attack is typically enough to dispatch a zombie, but you're better off shooting a zombie several times first. Zombies start out able to absorb four shots to the chest before a fifth one kills them. You can thus rack up points by shooting them four times, then taking them out with a melee attack. In later rounds, you can employ a similar strategy, while using more bullets before dealing the killing blow (since the zombies gradually grow tougher).
Invest in Up'N Atoms (Zombies Mode)
Early in a round, the best purchase you can make is Up'N Atoms. Once you spawn in the map, head to the far left and enter the small office, then turn on the power. Exit the office and make your way to the right to find the perk machine. You can purchase the Up'N Atom to revive yourself in single-player (the cost is $500), or to more quickly revive fallen allies in multiplayer ($1,200).
Pack-a-Punch Portal Locations (Zombies Mode)
There are four Pack-a-Punch portal locations, which you can activate to reveal a new portal that will take you to the machine itself. You can use it for 5000 points, within a match. You can find the portals (and switches to activate them) in the following locations:
Astrocade
In the Journey Into Space area, make your way to the arcade and check the wall for the power switch. You will find the portal just to its right.
Galaxy Journey
In the Journey Into Space area, follow the path behind the DJ to reach the switch. Then backtrack to the DJ to find the portal.
Kepler System
Starting from the center of the map, open the first door on the left in the Kepler District and proceed upstairs. The switch is on the wall, and you can find the portal downstairs.
Polar Peak
Look upstairs in the Polar Peak district. First unlock a door so you can go upstairs, then look for the power switch on a wall. Finally, head back downstairs to access the portal.
Souvenir Coin Combinations (Zombie Mode)
You can combine the colored souvenir coins you find in different combinations to access powerful traps and items, as noted below (turn in coins in the order indicated for the particular reward you want):
Blue, Blue, Blue - Sentry Gun
Green, Green, Green - Repcrator
Red, Red, Red - Medusa Device
Blue, Blue, Green - Electric Trap
Blue, Green, Green - Boom Box
Green, Green, Red - Sentry Turret
Green, Red, Red - Boom Box
Red, Red, Blue - Fireworks
Red, Blue, Blue - Window Laser Trap
Red, Blue, Green - Kindle Pop
Specialist Mode
Complete the game once on any difficulty.
Tuff 'Nuff (Zombies Mode)
You can withstand more hits from zombies if you secure the Tuff 'Nuff perk. You'll have to visit the perk machine first, however. To do so, enter the Journey Into Space portion of the park (it's located to the left of the main teleporter, as you face it). Inside that area, make your way up the flight of stairs just beyond the Galaxy Journey portion. Look in a corner to the right to find the machine, and prepare to spend 2500 points to activate the valuable perk.
Various Steam Achievements
Achievement
How to unlock
Aces High
Clear half of the most-wanted board.
Ante Up
Get your first kill on the most-wanted board.
Batteries Not Included
In Spaceland, create an Exquisite Core.
Black Sky
Complete Black Sky.
Boots on the Ground
Go 2 minutes without double jumping or wall running in a mission where these abilities are available.
Brain Dead
In Spaceland, play 30 games and get to scene 10.
C12
Kill a C12 by doing a right rodeo, a left rodeo and by blowing off multiple limbs.
Captain's Log
Use the computer in the Captain's office.
Danger Close
Kill 15 enemies with a zero G grappling hook.
Dominion
Win 5 online matches in Multiplayer.
Fangs Out
Earn your first Jackal item (weapon or upgrade).
Fully Equipped
Earn all equipment upgrades.
Gear Up
Find your first equipment upgrade.
Get Packed
In Spaceland Pack-A-Punch a weapon.
Gravity Kills
Kill an enemy while floating in your own anti-gravity grenade.
Gun Nut
All weapons scanned.
Hoff The Charts!
In Spaceland, unlock David Hasselhoff.
I Love the 80s
In Spaceland, find the MW1 and MW2 songs.
Insert Coin
In Spaceland, play every Arcade game at least once.
Jackal Ace
Earn all Jackal weapons and upgrades.
Make it Personal
Load out with a custom weapon.
New Gun Collector
Scan your first weapon!
Operation Black Flag
Complete Operation Black Flag.
Operation Blood Storm
Complete Operation Blood Storm.
Operation Burn Water
Complete Operation Burn Water.
Operation D-Con
Complete Operation D-Con.
Operation Dark Quarry
Complete Operation Dark Quarry.
Operation Deep Execute
Complete Operation Deep Execute.
Operation Grave Robber
Complete Operation Grave Robber.
Operation Phoenix
Complete Operation Phoenix.
Operation Port Armor
Complete Operation Port Armor.
Operation Pure Threat
Complete Operation Pure Threat.
Operation Safe Harbor
Complete Operation Safe Harbor.
Operation Sudden Death
Complete Operation Sudden Death.
Operation Taken Dagger
Complete Operation Taken Dagger.
Operation Trace Kill
Complete Operation Trace Kill.
Peace to the Fallen
Listened to all of the death letters of the fallen.
Peek-a-boo!
Kick open a door, peek open a door, and throw a grenade while peeking a door.
Reality TV
Watch a news cast.
Rising Threat
Complete Rising Threat.
Rock On!
In Spaceland, craft a Weapon of Rock.
Royal Flush
All SDF Aces and Captains killed.
Serious Gun Collector
Scan 10 weapons.
Sooooul Key
In Spaceland, recover the piece of the Soul Key.
Sticker Collector
In Spaceland, find all of the quest items and complete the sticker pack.
Targets of Opportunity
Complete all ship boarding side missions.
The Bigger They Are
In Spaceland, defeat 5 Brutes in one game without dying.
The Longest Day
Complete all Single Player missions on Veteran.
Top Gun
Complete all Jackal-only side missions.
You Know Nothing
Kill Kotch before his speech ends.
YOLO Mode
Complete the game on the Specialist Mode difficulty setting.
You Know Nothing
The actor portraying Admiral Kotch is Kit Harington, perhaps most well known for his role as Jon Snow in the Game of Thrones television show. The trophy/achievement titled "You Know Nothing" is a reference to the quote "You Know Nothing, Jon Snow." In the television show, the Wildling character Ygritte spoke those words to Jon Snow.
In order to earn the trophy, you will have you kill Admiral Kotch.
