• started to make this guide to be able to unlock the full game, I hope it will be of help to you.
  
• This guide is not complete yet, in the final chapters I have not recorded or created the gifs, sorry but I will do it as soon as I can.
  
• This guide has 45 gifs, so you should go for a glass of water to hydrate your body and come back. All files are hosted on Giphy.

I have also included the name of the map so that they can open it from the console, for this they must have the console activated and type "map" press space and then paste the name of the map.

In certain maps you will appear without weapons, to obtain weapons open the console and type sv_cheats 1 this will open the console. Then you must activate impsulse 101 cheat to get all the weapons. Before continuing, save your game and restart the game.

If sv_cheats 1 is enabled, no achievement will be recorded.

⠀⠀⠀⠀⠀⠀⠀In the first chapter there is no lambda symbols.

⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀    keep going down.⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀  

⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
Achievement Progress
Lambda Locator (1/45)

• Upon meeting Alyx Vance, she will bring Gordon towards Kleiner's Lab. The entrance to the lab is disguised as a Dr. Breen's Private Reserve machine, with a lambda logo to the right of it. While this lambda symbol only denotes a Resistance base, it counts towards the Lambda Locator achievement and cannot be missed.
• Map: d1_trainstation_05

⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
Achievement Progress
Lambda Locator (2/45)

• After dealing with the Metrocops in the tunnels, Gordon will be tasked with using an oncoming train to get across a gap. Across the gap is a ladder leading to a building with wooden planks covering the entrance. After breaking these, Gordon will see a lambda logo to the left with the associated cache.
• Map: d1_canals_01

⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
Achievement Progress
Lambda Locator (3/45)

• Shortly following the last cache, Gordon will have to fight some additional Metrocops, which can be made quick work of with explosive barrels. Along the path is a broken fence, which can be jumped over. A vent with a lambda logo over it can be seen around the pathway. Entering the vent, Gordon will be greeted with the associated cache. This lambda cache cannot be missed.
• Map: d1_canals_01

⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
Achievement Progress
Lambda Locator (4/45)

• Arriving at Station 1, Gordon will have to dispatch the oncoming Metrocops. Once dealt with, an explosive barrel must be destroyed in order to continue on the path. At the end of the path is a tunnel infested with Barnacles. At the entrance, a lambda logo can be seen to the left, next to a car. Over the car is the associated cache under a fallen oil tanker.
• Map: d1_canals_01a

⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
Achievement Progress
Lambda Locator (5/45)

• After completing a see-saw physics puzzle, Gordon will encounter a Hunter-Chopper, which will have to be maneuvered around. Avoiding the Hunter-Chopper fire and continuing on the path will lead a door blocked by a barrel, which can be moved aside. Inside is small set of stairs, leading to a narrow room with a sewer grate where a lambda logo can be spotted underneath. To the right is a ladder, which can be used traverse underneath the sewer grate to find the associated cache, next to a rotting corpse.
• Map: d1_canals_02

⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
Achievement Progress
Lambda Locator (6/45)

• Shortly after escaping the underground, Gordon will have to dispatch of Metrocops. Afterwards, a water turbine will be encountered, with a small underwater passageway which leads up to a steam pipe. The path of the pipe will lead to a room with Barnacles, which can be made quick work of with an explosive barrel. At the end of the path is a lambda symbol to the right of wall, next to some breakable wooden planks. Underneath the pipe is the associated cache, next to a rotting corpse.
• Map: d1_canals_03

⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
Achievement Progress
Lambda Locator (7/45)

• Upon leaving the sewers, Gordon will be met with a ladder which leads down to a narrow passageway where Metrocops will grapple down to fire, along with Manhacks. After dispatching of them, Gordon is met with a passageway leading back into the sewers, which leads to a narrow room with a ladder leading up to pathway with wooden planks. To the left of the ladder is a lambda symbol. Taking the path, Gordon will find the associated cache next to a second lambda symbol.
• Map: d1_canals_05

⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
Achievement Progress
Lambda Locator (8/45)

• Immediately after last cache is an exit out of the sewers, which leads outside to toxic waste. To the left are some wooden planks leading up to pipes. Climbing the pipes, Gordon will find the associated cache, next to a rotting corpse. There is no lambda symbol to denote this cache.
• Map: d1_canals_05

⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
Achievement Progress
Lambda Locator (9/45)

• After obtaining the Airboat, Gordon will drive through toxic waste, which will lead out to Station 7. On the way, Gordon will find a lambda symbol directly ahead on a wall. On the right is a ladder, which can be climbed to find the associated cache.
• Map: d1_canals_06

⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
Achievement Progress
Lambda Locator (10/45)

• Approaching Station 7, a lambda symbol can be seen painted on a wall, as well as on a container suspended by a crane containing the cache. Inside, there are two Zombies which Gordon will need to take care of. A set of stairs will allow Gordon to shimmy on top of wooden planks, leading to a ladder where a Headcrab will jump down to attack Gordon. Upon reaching the top, a barrel blocking the pulley must be hit the Crowbar, allowing the container to drop into the water. Inside is the associated cache.
• Map: d1_canals_06

⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
Achievement Progress
Lambda Locator (11/45)

• Upon completing the barrel puzzle and using the Airboat to cross the gap, Gordon will hear a Combine Dropship passing by. Shortly after, a second one can be spotted the path ahead, with Metrocops exiting from a container. Next to the Dropship is lambda symbol next to a broken sewer grate, with a tunnel leading to the cache. Entering the tunnel, Gordon will have to swim underwater into a small cave, where the associated cache can be seen. However, a Zombie will pop from the water and attempt to attack Gordon, which must be dealt with.
• Map: d1_canals_06

⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
Achievement Progress
Lambda Locator (12/45)

• Shortly after leaving the APC garage, Gordon will have to maneuver down the canals, avoiding APC and Metrocop fire. Upon reaching the second APC, a lambda symbol can be spotted underneath it. Avoiding the missile fire, Gordon can crouch under broken sewer grating to enter the cache. The associated cache can be seen next to a hole, where a Headcrab will attempt to attack Gordon. Metrocops will grapple down from the APC to fire at Gordon, which must be dealt with.
• Map: d1_canals_07

⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
Achievement Progress
Lambda Locator (13/45)

• Avoiding APC missile fire, Gordon will enter a tunnel, where a lambda symbol can be spotted on a wall next to a pulley system. One pulley has the associated cache, while the other has cinder blocks preventing the cache from moving. Upon removing the cinder blocks, the cache will drop down, allowing the supplies to be taken.
• Map: d1_canals_08

⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
Achievement Progress
Lambda Locator (14/45)

• Escaping from Gate 5, Gordon will come across a bridge with train cars on top. Underneath the bridge, a lambda symbol can be spotted behind the bridge pillars, next to the associated cache.
• Map: d1_canals_08

⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
Achievement Progress
Lambda Locator (15/45)

• While being chased by the Hunter-Chopper, Gordon will enter a tunnel filled with toxic waste. A lambda symbol can be spotted on a wall on the left, next to a platform held up by wooden supports. The Airboat can be used to destroy the supports, dropping the associated cache.
• Map: d1_canals_09

⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
Achievement Progress
Lambda Locator (16/45)

• Driving through more toxic waste while evading the Hunter-Chopper, Gordon will travel through a brief tunnel leading to a water channel. The walls can be walked on, with one side leading to a dead end where the associated cache can be found. There is no lambda symbol to denote this cache.
• Map: d1_canals_10

⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
Achievement Progress
Lambda Locator (17/45)

• Upon exiting the water channel, Gordon will come under fire by Metrocops grappling from a bridge. Next to the bridge are two small tunnels, which can be entered via the Airboat. Inside the rightmost tunnel is the associated cache. There is no lambda symbol to denote this cache.
• Map: d1_canals_10

⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
Achievement Progress
Lambda Locator (18/45)

• Navigating through more water channels, Gordon will be under fire from an APC, which can be destroyed with the newly acquired Airboat gun. Traversing through the channels, Gordon will meet a fork in the path, with a lone Metrocop on the right, which can be dealt with through an explosive barrel. Taking the rightmost fork will lead to an abandoned outpost where Headcrabs will attempt to ambush Gordon, as well as a Zombie. A ladder can be climbed leading to the associated cache.
• Map: d1_canals_12

⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
Achievement Progress
Lambda Locator (19/45)

• Upon arriving at Black Mesa East, a lambda symbol can be spotted next to a ladder near the water. While this lambda symbol only denotes a Resistance base, it counts towards the Lambda Locator achievement and cannot be missed.
• Map: d1_eli_01

⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
Achievement Progress
Lambda Locator (20/45)

• Entering Ravenholm, Gordon will have to fend of multiple Zombies throughout the deserted town, eventually meeting Father Grigori atop a balcony. Gordon will have to enter a building in order to turn off an electric grid preventing access to the next area. Upon entering the building, stairs leading to two turbines can be spotted, with a lambda symbol painted next to one. A vent can be broken on top of the leftmost turbine, leading back outside to the associated cache.
• Map: d1_town_01

⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
Achievement Progress
Lambda Locator (21/45)

• Later in the chapter, the player will soon encounter car crushing traps. Using the switches provided, one can get atop the car and ride it up. The player will spot a Lambda symbol below a fence. Hop over the fence and head into the enclosed corner. The cache can be found here.
• Map: d1_town_01

⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
Achievement Progress
Lambda Locator (22/45)

• Shortly, the player comes across Father Grigori again. This time, he'll be shooting Zombies, opposite from Gordon's position. Clear the area of Zombies, from top to bottom, then climb a ladder to proceed atop the building. At the top, walk to the end of the beam and turn left, where the player will see a hole in a roof with a Lambda inside. Deep inside is the cache, as well as a Fast Headcrab.
• Map: d1_town_01a

⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
Achievement Progress
Lambda Locator (23/45)

• The final cache of the chapter is located immediately after the end of the Ravenholm mine shaft. Above the archway are some supply crates, accompanied by a Poison Headcrab. Behind some ducting is the cache.
• Map: d1_town_05

⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
Achievement Progress
Lambda Locator (24/45)

• Once acquiring the Scout Car, follow the faint track in the sand up a hill and the player will come across a gap between a bridge. Use the turbo speed to get across the bridge. Around the next corner is a Lambda symbol marking this location, clearly visible on a red shack at the side of the road. Inside the shack is the cache.
• Map: d2_coast_01

⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
Achievement Progress
Lambda Locator (25/45)

• At the sight of the first Thumper, exit the Jeep and there will be a small house next to the Thumper. It appears to be locked from the inside, but the house can be accessed via the cellar. A Lambda symbol can be seen obscured by tires. Break the cellar door and continue into the cellar. Inside will be a Grenade crate and a Poison Zombie, which can be taken out with the Grenades provided. Once it has gone quiet, the cache can be reached by stacking crates and barrels to get above.
• Map: d2_coast_03

⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
Achievement Progress
Lambda Locator (26/45)

• After the Gunship battle at NLO and the crane segment at Dock 137, another Gunship will be encountered after jumping over the bridge. Deal with the Gunship using the crate of rockets in one of the cars blocking the road ahead. Soon after the Gunship is down, head on the road and stop at the blue van. A Lambda symbol is marked at this location. The van contains the cache.
• Map: d2_coast_04

⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
Achievement Progress
Lambda Locator (27/45)

• After driving for some time, the player will come across a Petroleum Station with a surplus of Combine Soldiers and a Force Field blocking the Scout Car from entering. The force field can be disabled by removing the chocs under an APC. Near the APC will be a fenced area with a white gas tank and a Lambda symbol. Use a barrel to get inside the fence, which has is partially torn down. Head inside the enclosed area and inside is the cache.
• Map: d2_coast_05

⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
Achievement Progress
Lambda Locator (28/45)

• The last location in this chapter can be found right before Bridge Point. After exiting the tunnel, a Dropship will be seen dropping Combine Soldiers at Bridge Point in the distance. Upon approaching the area, there is a large jagged outcrop of rocks on the left. Enclosed behind the rocks is the cache in a small boarded area.
• Map: d2_coast_07

⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
Achievement Progress
Lambda Locator (29/45)

• Drive up to the very end of the map, until some oil tankers start blocking the path. An unopened gate is blocking the Scout Car from entering, but it will open after finding 3 car batteries in the area. Above the doorway leading to the toilet is a Lambda symbol on the roof. Use the Gravity Gun to grab the single Energy Ball canister.
• Map: d2_coast_09

⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
Achievement Progress
Lambda Locator (30/45)

• The second and last cache of this chapter can be found during the sand puzzle segment. In the open area across the rocky outcrops, a wooden shack with no roof can be seen. The easiest way to reach the shack is by using the long wooden plank in the neighboring outcrop. Once reaching the shack, start climbing above the shack by stacking barrels and crates. Once reaching the top, a white shack with a Lambda symbol can be seen, which is accompanied by the cache.
• Map: d2_coast_11

⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
Achievement Progress
Lambda Locator (31/45)

• Not far into Nova Prospekt is the first cache. Once reaching the area with 2 Turrets, the player will spot a Lambda symbol next to a door. Break the planks on the broken glass and the cache will be inside.
• Map: d2_prison_02

⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
Achievement Progress
Lambda Locator (32/45)

• After spotting the dead Vortigaunt on the chair, head upstairs to the next floor. Beyond the tripwire, the player will see a Lambda symbol marked near a door. The cell door next to it can be slid open to reveal a secret cache.
• Map: d2_prison_03

⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
Achievement Progress
Lambda Locator (33/45)

• The final location in this chapter is in the laundry room with the ambush set up. In the room, the player will see a small passageway over the short railing to the right. Hop over the railing and the cache can be located in the small room. Stay sharp, as a Poison Zombie is in one of the rooms.
• Map: d2_prison_05

⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
Achievement Progress
Lambda Locator (34/45)

• The only cache in this chapter is found right after Gordon and Alyx split up again. She'll open a blocked gate for you and in the area beyond is a vending machine. Atop the vending machine is a small cache.
• Map: d2_prison_06

⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
Achievement Progress
Lambda Locator (35/45)

• Immediately after emerging from Kleiner's lab with Dog, to the left, the player will see a dumpster with a crate near it. Use the crate to get atop the dumpster and the cache will be seen easily visible next to the wall.
• Map: d3_c17_02

⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
Achievement Progress
Lambda Locator (36/45)

• A little while after encountering the Combine Hoppers, the player will enter a courtyard with Civil Protection units firing at the player. There is a surplus of explosive barrels, with one near a tiny red shack. Behind the barrel is a metal sheet, with the cache located inside.
• Map: d3_c17_04

⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
Achievement Progress
Lambda Locator (37/45)

• After running through a series a buildings, the player will come through a underground tunnel where Turrets stand watch over a hole in the wall. Through the hole, the path will split into 2 individual paths, one leading upstairs and one leading to the next area. Head up the stairs and the player can see a cache behind a blocked gate. Use your Gravity Gun to get the supplies behind the gate.
• Map: d3_c17_05

⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
Achievement Progress
Lambda Locator (38/45)

• An underpass full of Manhacks will be ready to attack the player. In the second segment of the underpass, after going around a wall of rubble, turn back towards the collapsed roof. The cache can be found near the glowing fire.
• Map: d3_c17_06a

⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
Achievement Progress
Lambda Locator (39/45)

• After one of the Resistance fighters lets down a bridge for Gordon, keep going until encountering another bridge. If the location is missed, the Lambda cache is right behind the wall inside the ruined building.
• Map: d3_c17_06b

⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
Achievement Progress
Lambda Locator (40/45)

• The player will spot this Lambda as descending through an infested building full of Zombies and Combine Soldiers. At the lowest elevation, the player will spot a Lambda through a doorway. The cache is blocked by a fence, which can be accessed using the Gravity Gun.
• Map: d3_c17_06b

⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
Achievement Progress
Lambda Locator (41/45)

• After a standoff with Alyx in the plaza area, the player will proceed to an underground area. Head forward until reaching a room with a bottomless pit. Down below the Lambda symbol can be seen and accessed with a ladder.
• Map: d3_c17_08

⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
Achievement Progress
Lambda Locator (42/45)

• The player will come across Combine fighting off zombies, this time in a sewer looking area. After dropping down into the lower area, a passageway leads off to the left. Follow this, and shortly the player will come across a ladder to the right. Ignore this ladder and continue onward. The player should notice the Lambda symbol ahead, where the passage splits. The cache is hidden in a hole in the wall, which can be obtained by using the Gravity Gun.
• Map: d3_c17_08

⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
Achievement Progress
Lambda Locator (43/45)

• This cache is very close to the previous cache. Standing in front of the last cache, look to your left and the player should be able to see another passageway with capped metal pipes inside. Climb over the pipes and the cache can be found just ahead.
• Map: d3_c17_08

⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
Achievement Progress
Lambda Locator (44/45)

• The last location in this chapter can be located in the open room with the lift. Fight to the top, but before dropping down to the next level, navigate around the red corrugated building using the narrow ledge. The player should see a faint Lambda symbol behind a wall. The cache will be in the same area.
• Map: d3_c17_08

⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
Achievement Progress
Lambda Locator (45/45)

• The final cache in the game can be found very far into the chapter. After getting to the building with a Soldier ambush and the Strider under the tunnel, head up to the highest level and try to avoid Strider fire if possible. After getting past the area, the player will find a bunch of crates and should unlock Lambda Locator if all previous caches have been obtained.
• Map: d3_c17_12b

https://psteamcommunity.yuanyoumao.com/sharedfiles/filedetails/?id=2183726238