This guide will tell you how to get the Lambda Locator achievement instantly. Similar guides existing on steam create a custom map that gives you the achievement, but I will tell you how to do it without downloading ANYTHING.
 
 

Setting Up Game File

READ BOLD FOR INSTRUCTIONS ONLY, NO CONTEXT
 
 
Here is how you do it.
 
 
Right click the installed game in steam, and go to Manage > Browse local files > hl2/gamestate.txt
 
 
The above hl2 is the directory of course, not the .exe
 
 
Scroll down to 31, which is the achievement data for Lambda Locator.The data is a hexidecimal number tracking whether or not you’ve seen/gotten the associated lambda cache. In binary, it has 45 ones or zeros. One is you got it, zero is you don’t.
 
 
So we’re going to replace whatever you got with all lambdas EXCEPT ONE. It won’t trigger on Steam if you set it to the hexidecimal for seeing every location (0x00001FFFFFFFFFFF). So we will set it to every location seen except the first one.
 
 
Change the data to the following:
 
 
0x00001FFFFFFFFFFE
 
 
This may look like it represents every location except the last one, but binary order is right to left. So the above hex represents
 
 
111111111111111111111111111111111111111111110
 
 
and that 0 means you have not seen the first one.
 
 
 

Get First Lambda

In game, check achievements to make sure you did the previous steps correctly. It should say:
 
 
Lambda Locator 44 / 45
 
 
Now, start a new game at the Chapter “A RED LETTER DAY”
 
 
Rub against the Lambda before Alyx opens up the vending machine.
 
 
The achievement should trigger shortly after you walk into the lab.
 
 
That’s it! Congratulations.
 
 
If you want a guide on how to get the achievement legit here is a great one – [steamcommunity.com] 
 
 
If you want a guide on the other achievements, here is what I used – [steamcommunity.com] 
 
 

 
 
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