Black Mesa: Definitive Edition - 14b - Lambda Core [Hard]

Chapter 14: Lambda Core - Part Two

After activating both coolant pumps and swimming through the flooded auxiliary tank, Freeman emerges at the base of the Lambda Reactor, which he promptly activates. However, the reactor core is highly unstable, generating dangerous beams of energy and small intradimensional portals. Gordon successfully skirts these hazards and makes his way to the tip of the reactor, where the Lambda Team tells him the brutal truth: the Lambda Reactor is capable of opening a portal to an alien borderworld known as Xen, where the mastermind behind the invasion resides. To end the invasion and save Earth, he must venture into Xen and kill it. Armed with his deadly arsenal and a new tool - the Long Jump Module, Freeman must fend off one final alien assault as the Lambda Team prepares the portal.

Playlist with all completed chapters:
   • Black Mesa: Definitive Edition (Full Playt...  

Notes:
The notes section for this video was too long to fit into the description, so I've included the notes in my pinned comment instead - please refer to that comment for the full set of notes

Trivia:
The Lambda Reactor is divided into four levels as shown by the diagram at 9:01. Level D is the base of the reactor where Gordon emerges from the coolant (0:43). Level C is the area that he teleports to by jumping into Port 7 (15:00). Level B is the section of the core with all the ports (9:50). Finally, Level A is the tip of the reactor, where the Survey Team suits up and gets sent to Xen via the main portal (25:05)
The area at 1:15 was first shown in the 2008 trailer for the game
The energy discharges from the reactor at 2:20 used to leave scorch marks on the walls so that players could more easily figure out where they need to crouch/jump. These do not appear in the current game (probably a bug)
The guard and scientists at 4:49 can be killed by using the Tau Cannon to shoot through the grate
The G-man's ninth and final appearance in the game aside from the ending sequence (5:55). Gordon later visits the same room he is in at 10:35
The Guard's comment at 7:22 is a reference to the 1986 movie "The Fly", where a scientist experiments' lead to him getting grotesque mutations. The latter part of his quote "..until the gun goes click" may also be a reference to a similar line from the 1998 film "The Big Lebowski"
The writing in blood at 8:57 may be a reference to the 1980 movie "The Shining", where Room 237 is a haunted hotel room. In the game, ports 3 and 4 are on separate levels, which is probably why the devs had to change it from "237" to "247"
The Guard's comment at 12:21 may be a reference to the Pizza Code Mystery, an ARG within the game
The shelf at 13:02 used to be one of the locations of the Purple Hat, which players can carry to the end of the game (through Xen) to get a special ending cutscene. However, with the introduction of an achievement to carry it from the start of the game to the end, the hat was moved to Chapter 3 instead
The middle ring section of the core at 15:00 used to move up and down in previous versions of the game. It has now been rendered static to decrease the amount of platforming required to get to the centre
Gordon can disable the friendly turrets at 17:00 by shooting them
The Supply Depot at Core Level A (17:00) has been significantly expanded in Black Mesa. In HL1, there is only one scientist and guard, and not as many rooms and equipment. However, Black Mesa omits the scientist aiming a shotgun at Gordon when he first arrives at the Supply Depot entrance
Killing anyone in the Supply Depot will trigger a game over screen, however the surviving scientists will react positively before the game reloads, saying phrases like "Stupendous!"
Unlike HL1, the Long Jump Module features a boot up animation, similar to the HEV suit, upon equipping it (19:32)
In HL1, Gordon can get the security guard (Hunter) at 19:50 to follow him to the portal, where he will help defend against the breach. In Black Mesa, he just stays at the armory and cannot be further interacted with
In HL1, the Alien Controllers will actively attack the scientist operating the portal controls (25:25) and try to kill him. In Black Mesa, they do not do this, although the game files contain several voice lines from the scientist that implies that this was to happen in pre-release versions of the game
The sound effect at 26:16 is also the sound a Strider makes when charging up its Warp Cannon in the HL2 games
If noclip is used to get inside the room with the portal controls (25:25), it can be seen that the scientist is actually just chatting with a fellow scientist on an online messaging program. This same computer screen can be seen in the opening moments of Anomalous Materials (Chapter 2), where it is adjacent to the entrance blast doors
Gordon is shown to be travelling through a wormhole at 28:26
The ending sequence, where Nihilanth is teased, is not in HL1