I am on the Xbox 360 and have all 3 discs installed on the hard drive. I played the entire game on nightmare and just finished it the other day and only 1 achievement unlocked. I did not change difficulty at all. Has anyone else encountered this and is there any way to get the achievements to unlock without replaying the entire game? Bethesda/id feel free to check my xbox account to verify if needed. My screen name is my gamer tag. Thank you. BTW I remember playing Wolfenstein, Doom, and Quake on the pc when they came out (I did find the 3 easter eggs in the game, nice!). Keep up the great work!

I have 980g just doing legends now can't say I have had that problem but I did go thru first on hard then went thru on nightmare. An no unless you have a previous save you gotta go from the beginning frustrating I know lol. I was doing collectibles got to the second disc an realised I'd missed ONE! An had to start again still had fun tho.

I was talking about the achievement for completing the game on nightmare. I have no achievements for completing the game on any difficulty. I am going to get the collectables in the future.

Achievements for completing the game on a given difficulty are awarded only for the lowest difficulty the game was set to for the entirety of the player’s progression.