Assault on X64-2 is the first mandatory story mission in Episode 3.
Mission Summary[]
EAF claim that, according to information obtained on the Cycloid Mothership, planet X64-2 is actually certain alien bastards homeplanet. Or, at least, one of their major colonies. They send one of their battleships to raid this planet. AMC team decided to join them. However, upon arrival, they noticed that the planet is already devastated by someone else...
Gameplay[]

Kill all the enemies including the fat commanders with the mounted gun. Then you'll be dropped to the ground. Take the elevator up. Head through the nearest door. Inside, go down and hit the switch. Head out, go left and take the elevator down. Head past the tower and up the hill. There, you'll see fellow AMC soldiers. Grab the beacon and place it on the giant battlelord door. Head back and use the drone to destroy the door. Inside, kill all aliens, go upstairs and hit the switch on the wall, then head back to the tower. Kill the Battlelord and the Cyber Enforcer.

Hard to see elevator on the tower
There is a tiny lift on the inside that's hard to see. Take it up. You'll find a vent break. Jump in.
Under The Surface

You can talk to and rescue the grey aliens in here. Go into the side, kill the Battlelord and use the fighter ship. Fly straight and land on the platform. Inside the red large room, head up to the control room and then drop onto the egg conveyor belt, then go inside and follow the tunnel to another big room. On the right is an armory if you want. Cross the bridge to the other side. You'll find a large room with lots of holograms. Go to the right semi opened door. Grab the blue rune key on the other side. Head back. In the room with the bridge, open a door with an armory and switch inside to open the adjacent door to go back to the ship. Head right into the lower tunnel. Land, hit the switch, and then continue moving forward. Land. Use the lift on the left. Go inside. If you use the lift, it will lead you back to the start. Go up the slope to a battelord door and open it with the blue key. Watch the EDF soldiers mutate and fight the Chryssalids. You can use the jumping platforms to help you.

NOTE: If you replay this mission after finishing Episode 3, in 3.5 redux, there is a bug where it can send you to the wrong base. To fix this, just start Episode 3 again and head to the red portal.
Secrets[]
There are no secrets in this level.
Other Items of interest[]
Beyonders invaded the Cycloid's homeworld
- You can rescue 3 alien scientists at the start of Under the Surface.
- Near the dead EDF soldier is a spirit Rusty can talk to, located in the cave not far away from the tower.
Trivia[]
- The tower you see in the distance in X64-2 is recreated from the tower in the final mission of the Imperium mod (which takes place on the same planet), with permission from the Oostrums.
- After defeating the Chryssalids, when AMC Squad arguing what to do with the Cycloid Bioweapon, Micky claims that it must be destroyed, otherwise it could bring an "XK-class end-of-the-world scenario". This is likely a reference to the SCP Foundation.