What I would suggest to do if you just want to earn 1 gamerscore is to mod it via Horizon. That's what I would do personally, because they wont ban you if you did it as an offline achievement.
What I would suggest to do if you just want to earn 1 gamerscore is to mod it via Horizon. That's what I would do personally, because they wont ban you if you did it as an offline achievement.