In case you mess up this Achievement, including:-
Good, Neutral, and Bad.NOTE #1
finish the optional quest; The Power of the Atom
where Mister Burke
asks to blow up Megaton
because you CAN'T
do the XP glitch.
Simply start a New Game and buy or find 2 Frag Mines.
After that, fast travel to Megaton
(you need to discover the location first, for you to fast travel)https://vignette.wikia.nocookie.net/fallout/images/e/e7/Mega...
Make your way to Craterside Supply.https://vignette.wikia.nocookie.net/fallout/images/8/81/Crat...
Behind the Mercenary
standing against the wall, simply go behind him at the other side of the wall and plant a Frag Mine.
You have to disarm it quickly before it goes off and then pick it up. (Eventually, you will gain XP a lot faster)
Shortly after when you reach Level 7, at the end of the XP bar (nearly levelled up to Level 8) simply SAVE
the game and after that, get Good Karma and do good stuff.
I suggest starting the Church of the Children of Atom
quest to gain Good Karma.https://vignette.wikia.nocookie.net/fallout/images/6/60/Chil...
Also, donate 100 bottle caps to Confessor Cromwell.
Once you have your Good Karma maxed out, keep disarming the Frag Mine
to reach Level 8.
Once you have the Protector Achievement, Load the game again from the 1st save and then gain Bad Karma and then reach Level 8 for the Reaver Achievement.
When you gained the Reaver Achievement then Load the game again and do Good and Bad stuff to be Neutral and reach Level 8 and you will unlock the Mercenary Achievement.
You get the idea for reaching Level 14 and Level 20 with Good, Neutral, and Bad by using the XP glitch.NOTE #2
This trick will also work for you with the other Level Achievements, on the Broken Steel
I will advise you to save the game every few minutes. The reason for this is because sometimes people come into the shop and they randomly come up to you and the Frag Mine explodes and kills them. Obviously, it will go pear-shaped for you and you won't be able to do the XP glitch. If this happens, immediately
load up your last save.
I hope this helps and if you are confused about the XP glitch, then here is a video explaining to you, what to do.I also like to thank the YouTube user for uploading their video.Before you give me a negative vote, please explain yourself why you did it and I will be more than happy to improve my solution. Thank You.