While V1 usually disabled achievements, V2 stores achievement data locally in .ini or .dat files. Some advanced fixes even simulate unlocking Steam achievements visually within the game’s overlay (though they won’t sync to Valve’s cloud).
Copying and replacing files within the game's root directory. steam-fix v2
Assigning a valid Application ID (AppID) to a program so Steam recognizes it as a legitimate entity for networking purposes. While V1 usually disabled achievements