[Dont fear the reaper] Achievement uncredited upon completion

[Maid7]

*I beat the secret ending{No achievement}
~Choose both the paths after being uncredited my 1st run through it [Still no achievement]
~redid it 6 times after restarts and [STEAM] still did not give the achievement
~Any suggestions????will GOG be able to credit me the achievement or something?"
~Will i have to start a whole new playthrough?

 

[darkallnight]

Is this a PC only sort of thing? Because I'm pretty sure such achieve doesn't exist on Xbox.