Welcome to Dark Energy, the fourteenth and final level of Half Life 2.
The second transport pod
You are still in the transport pod as you move into a confiscation field, where your organic gravity gun is seized from you by a Combine Elite. Dr. Judith Mossman tells you not to struggle, and as you move forward you hear Dr. Breen. In the next room you see Eli Vance in a transport pod, who is mid argument with Dr. Breen, and as they argue Alyx is brought in contained in a transport pod. Dr. Breen continues to talk for a while, until eventually Judith seizes the opportunity to free you. As you are released from your transport pod you see Dr. Breen run off with your organic gravity gun. After making sure Eli is alright and saying goodbye, Alyx leads you after Dr. Breen. Alyx takes you to a lift, activates it and as you reach the top you see Dr. Breen ahead behind a forcefield, talking to a holographic projection of creature that you will learn about in Half Life 2 Episode One. Dr. Breen heads for another lift, leaving the organic gravity gun behind. Alyx takes down the forcefield, but Dr. Breen makes it to another lift.
Going after Breen
Alyx shows you the Citadel’s Dark Fusion Reactor, then gives you instructions. Charge your health and suit before getting into the lift and heading down. When the lift stops, go forward and left, where you will see Dr. Breen in an energy bubble. Head to your right, wait for the platform to start moving and go along the ledge by the wall towards the forcefield and energy streams. Go up the ramp, left and through the energy beams after removing the energy balls and throwing them at the Combine. Get onto the moving platform and go up to the next level. When the platform reaches the top, jump onto the next level, kill the Combine, go past the moving platform and along the walkway to the centre of the chamber. Get onto the platform, which will move around the central column before going up a level. Jump onto the floor, recharge your health and suit, kill the Combine and jump onto the next moving platform, which will again take you up. Jump onto the floor, kill the Combine, and go onto the next moving platform and up for the final time.
The game's finale is a frantic race against time. Go to the far end of the floor, so that the central column of the Dark Fusion Reactor is ahead and to the right, where you will see a shield dropping to reveal the teleportation portal. Fire an energy ball from one of the energy streams into the portal between the two metal rings. A set of shields will rise in the column and bugships will start to attack you from above. You must destroy all of the shields by hitting them with energy balls as quickly as possible, as if you take too long you will be killed by the bugships or destroyed by the portal radiation as Dr. Breen escapes. You will know when you have destroyed the shields; Alyx will join you before G-Man makes a final appearance and the credits roll.