Gordon emerges from an underground tunnel and finds himself at the foot of the Citadel, a large chasm of a crater the only thing separating him and the absurdly tall Combine tower. Upon finding a way inside, he comes across what appears to be a loading area for some prisoner pods, with a queue of them moving along a track and stopping at a walkway so that one can enter.
Climbing into one of the pods, Gordon is whisked through the interior of the Citadel and ends up getting glimpses of its various inner workings, from the Razor Train and Strider corridors to the Gunship repair bays. The pod eventually releases him and he drops down into a confiscation field. It grabs and destroys all of his weapons one by one, but the Gravity Gun is unaffected and ends up becoming supercharged instead. With an upgraded zero-point energy weapon now at his disposal, Gordon fights his way through an overwhelming amount of Overwatch soldiers sent to stop him from venturing further into the Citadel, all while Dr. Breen makes contact with and admonishes him via the tower's many computer terminals. Many pummeled Combine troops and a dead Strider later, Gordon ends up with no other way forward but to climb into a second prisoner pod. This one takes him straight up to Breen's office, where he and Mossman have been anticipating his arrival.
This chapter contains examples of:
- Disintegration Chamber: The Combine sterilization chamber used for the excision of quarantined malignants within the City 17 Citadel. This is done by a track of prisoner transport coffins that run throughout the entirety of the place and you happen across a loading platform for two tracks with one that loops through one of these chambers. Climb on in if you want to Press E to Die!
- 11th-Hour Superpower: The Gravity Gun becomes supercharged partway through the chapter, allowing it to kill enemies with a single hit and throw their bodies at other enemies with ease. Meanwhile, the suit chargers in the Citadel are able to charge Gordon's HEV armor up to 200 points and can also replenish his health, greatly increasing his survivability.
- Idiot Ball: Gordon Freeman climbed inside of a moving metal coffin in the Citadel just because he had no clue where else to go. Twice. Not that he had much in the way of other options, but still...
- Intercom Villainy: Dr. Breen uses the many terminals throughout the Citadel to contact Gordon and upbraid him for his destructive rampage against the Combine. The terminal screens can be destroyed to shut him up, but eventually he uses a large, indestructible Breencast monitor to deliver his ultimatum:Breen: Look, Gordon! Look at what you are throwing away! Is it worth it?!
- No-Gear Level: In the sense that you lose all of your weapons to a confiscation device, though you get a supercharged Gravity Gun to make up for it.
- Scenic-Tour Level: Gordon gets to ride through the Citadel inside two different prisoner pods and is given a thorough look at the Citadel's inner workings both times.
- Schmuck Bait: The first time you're meant to ride in a prisoner pod, you can choose between two tracks to ride on, one of which leads to a device that electrocutes every pod that passes through it. It goes without saying what happens if you choose to ride through that one.
- Shut Up, Hannibal!: Sort of: you can use the Supercharged Gravity Gun to either rip out or just blast the Breencasts. The last one is harder to silence, since Breen does it on an unbreakable screen... but luckily for you, there's a few of the Combine high-energy balls nearby which can be fired at it with the Gravity Gun if you really don't want to listen to him.
- Stupidity Is the Only Option: During a certain point in the Citadel level the player is left no choice but to climb into a Stalker pod in order to advance. And after being (of course) captured, stripped of your weapons, and escaping due to a Deus ex Machina, you are later required to step into another, identical, pod, and be captured again. Lampshaded by Breen, who congratulates you for delivering yourself to him so conveniently.
- Suspicious Videogame Generosity: Your protective suit has 100 points of armour when fully charged, and the wall chargers can give you 75 points (on easy). When you make it into the Citadel at the end of the game, the wall charger charges your armor up to 200 points, and they can fully charge your health as well (before you needed separate health stations that were usually but not always right next to the suit chargers, and which also only gave 75 health total). Uh-oh.
- Unusable Enemy Equipment: The weapons carried by Overwatch troops inside the Citadel disintegrate upon their death, preventing you from picking them up.
