Link:

https://drive.google.com/file/d/1bNVPJhE8E0DrRhOf1h2WII3w3xdEaURp/view?usp=sharing

Installation:
Once the file is downloaded, go to the following path and put the file in the "save" folder and that's it, just go into the game and do it!.

D:\User\Documents\RealRTCW 4.0\main\save

ATTENTION!:
Make a back-up of your original files, and then when you finish unlocking the achievement, put your original files back.

Once you have it installed, enter the game and select the file "Ach_PROTOSOLDIER" and start the game, you only have to stab the Proto Soldier once and you will kill him, then you will get the achievement.