Reunion is an achievement/trophy in Call of Duty: Advanced Warfare in Exo Zombies. It requires the player to complete all of Oz's challenges in the map Descent. This is the main story easter egg achievement.
Step 1: Override the encryptionEdit
The player needs to go to the Tidal Generator area. Along the spiral staircase, there are several valves on the wall. The player needs to shoot at the valves to turn them until a blue light shines above each of the valves.
Afterwards, head up the staircase and find a terminal on the second floor, and press the action button to interact with it. An-G will ask if the player wants to override the encryption to the data. Press the action button again, and An-G will say "Access denied". Oz will tell the characters to reroute the facility's power to this room.
Step 2: Deactivate the underwater security switchEdit
In the Lounge area, there is a door that leads to the underwater area. A player needs to stand by the door and hold the action button for a period of time to depressurize it. The player can leave the door if necessary and come back later to resume the depressurization process as it maintains the player's progress. Afterwards, a player needs to acquire a Goliath suit and go through this door.
Once the Goliath suited player is in the underwater area, they need to reach a switch that glows red, and interact with it. In the player's path, there will be a floating Host zombie that requires knocking over in order to pass through. Once interacted with the switch, it will then turn blue. After the Goliath player gets back inside the map, Oz will inform the player of a challenge coming in the next round.
Step 3: Drone ChallengeEdit
At the beginning of the next round, Oz will give the player(s) a challenge to complete. Around the map, there are five Treasure Drones that need to be destroyed to complete this challenge. The player has a limited amount of time to destroy each drone before it flies away, which would cause the player to fail the challenge. If that happens, they need to wait until the next round to redo the challenge from the beginning.
It is also recommended to do this step during the round, as the challenge will reset if all zombies in the round die. Once the step is completed, there will be a confirmation audio cue from Oz.
Step 4: Charging the capacitorEdit
In the Galleria area, there will be a small capacitor station that requires charging with electricity. The player needs to lure EMZs to this area, and let them hit the player, so that their energy can be absorbed by the capacitor. The capacitor requires several charges in order to hit 100%. Once finished, An-G will say "Capacitor is charged. Power diverted to Tidal Generator", followed by another quote from Oz.
Step 5: Grenade ChallengeEdit
For this round, the players will be given an unlimited amount of Contact Grenades during the round, regardless if the player has bought them or not. The player needs to use their grenades to kill zombies until the round finishes. The player cannot, however, use their guns, tactical grenades or any special scorestreaks against zombies. Once the player is done, there will be an audio cue from Oz.
Step 6: Jump puzzleEdit
On the spawn area of the map, there are several blue glowing platforms placed in specific patterns. The player needs to navigate around the platforms with the Exo movements, in order to reach the final platform (designated by a floating logo). Each time the player reaches the final platform, they will be bounced back to the map, and a new pattern will be arranged. There is a limited time for the player to stand on a platform, before it disappears, forcing the player to wait until it respawns. After doing this nine times, the step will be completed.
Step 7: Move ChallengeEdit
For the next round, the player's points will be constantly deducted the more they move, and they need to prevent it from reaching zero. If your points reaches zero, you will not be able to move. Basically, the player needs to do whatever they can to earn extra points: killing zombies, activating Power Stations, using Credit Dispensers, etc... Once the round is finished, an audio cue from Oz will confirm if the challenge is completed.
Step 8: Memory ChallengeEdit
Head to the Reception desk, where there will be four monitors. The monitors will display a different colored sphere on each of them, and the player needs to interact with them in the order they are shown, similar to the first step in Richtofen's Grand Scheme. After finishing the step, Oz will inform the player of another challenge in the upcoming round.
After completing this step, the experimental Upgrade Station will unlock.
Step 9: Friendly Fire ChallengeEdit
In this step, friendly fire will be enabled among the players. What the players need to do is to ensure they do not down each other, or the challenge will fail. In solo, AI-controlled characters will spawn in, and they can damage the player. If the AI characters are killed, the player receives a free weapon upgrade, similar to rescuing a survivor on the map infection. After finishing the round without any friendly fire casualty, the challenge will be completed.
Step 10: Numbers gameEdit
Head to the Tidal Generator room. Near the terminal on the second floor, there will now be a number panel display. The players have to alter the numbers on the bottom row so that it matches the numbers on the top row.
The four numbers are altered based on the players action: the first number depends on boost slams (which requires Exo Slam, and have to hit zombies to count), the second number changes when the player jumps, the third number changes based on wall weapon purchases (including guns and grenades), and the fourth number changes when zombies are killed.
Once finished, Oz will inform the player of another challenge in the next round.
Step 11: Rocket ChallengeEdit
Similar to the Grenade Challenge, in this round, players are given a MAHEM Mk 25 with unlimited ammo, which is the only allowed weapon for players to kill zombies. As with the previous challenges, players need to finish the round using only the MAHEM. Once finished, there will be an audio cue from Oz.
Step 12: Revisit Oz's memoryEdit
Go to the Tidal Generator, and activate the terminal on the second floor again. This time, the players will be teleported into a fragment of Oz's memory, resembling the courtyard in the starting area of Outbreak. Like the Friendly Fire Challenge in solo, AI-controlled characters will spawn in to fill the slots of missing players. The player controlling Lennox, however, will switch to controlling Oz. Players need to hold out against the zombies, which would come in two waves. Between the waves, there will be a conversation between the characters and Oz.
After finishing the second wave, the match will reset in "Double Feature" mode, which is essentially a hardcore version of the map. The achievement will then be unlocked upon the completion of the second wave.