Gordon reaches the old tram system - an archaic, rail-based one distinct from the comfortable, high-tech trams from the start of the game. At the start of the level, Gordon is informed by a security guard that he has a new mission: that in order to attempt to reverse the effects of the Resonance Cascade, the scientists of the top-secret Lambda Complex need Gordon to fire off a satellite delivery rocket into space. The problem being that the HECU marines killed the scientists at the rocket launch facility, and proceeded to abort the launch.
As a result, Gordon worms his way through the seemingly endless maze of tram tunnels; facing heavy resistance from both the military and the aliens until reaching the surface after sunset and breaching the rocket launch facility. Upon reclaiming the rocket launch area from the HECU troops, Gordon manages to fire the rocket, getting its payload into orbit successfully, before returning below ground.
This Chapter contains examples of:
- Absurdly Ineffective Barricade: Gordon gleefully plows through several of these on the tram.
- Antepiece: You're given some time to figure out how to operate the rail system before too many enemies show up.
- Bizarrchitecture: Before reaching the High Altitude Launch Center, Gordon encounter the rocket he's supposed to launch twice, first at the base, then at the medium level. However, if backtracking after launching the rocket
, the rocket will still be present in the two previous maps. It's not clear if it's just a programming oversight, or they're supposed to be three different rockets, as putting all the maps together shows that the three instances end up in different spacial locations. - Cutting the Knot: The player can beat the chapter the intended way, unlocking paths forward for the rail car and using it to progress... or the player can just foot it for most of the chapter and Sequence Break at several locations. The only places riding the tram are required is to destroy some concrete barriers, go up an elevator shaft, and pass through some electrified water.
- Enemy Chatter: On the surface, you stumble across two soldiers speculating that Gordon started the entire Black Mesa disaster and entertaining revenge on Gordon for him slaying fellow troops.
- Hell Is That Noise: There's two times early in the level (the flooded tram area and the bottom of the rocket) where a distant, echoing scream, can be heard of some strange creature. We never find out what it was that made the sound.
- It's Personal: The HECU have started to notice Gordon, and consider him a personal enemy: they talk smack at him during fights, and leave (Poorly spelled) graffiti to threaten him, with such gems as "YORE DEAD FREEMAN" among them.
- Locomotive Level: Small electric rail cars are the primary transportation units for reaching the surface. The HECU has anticipated this and set ambushes to stall progress.
- Sequence Breaking: Being a tram track maze, the tram will sometimes go off in directions that is off the main path. Thus, they can be skipped if you just walk along the main path track. This is especially the case in the 3rd tram section where the second box transporting room can be skipped entirely if you move on foot.
- Sidetrack Bonus: Due to basically being a large tram maze, there's a lot of optional areas throughout the level for supplies and running into enemies. One noteworthy optional area is the loading map for the bottom of the satellite delivery rocket as there's absolutely no need to go to this section. Other than picking up supplies, this map area ends at a dead-end in the form of a destroyed elevator.
- Stuff Blowing Up: As if the claymore mines, hand grenades, and SMG-mounted launcher weren't enough, Gordon now has the ability to chuck C4 around.
