I imported a character that had all achievements completed on the 360. This includes discovering all named locations and completing all side quests for both the main story and the DLC.
I was able to unlock some of the location / side quest related achievements:
- World Traveler, Arctic Explorer, Urban Explorer, Highlands Explorer, Blight Explorer (all main campaign location achievements unlocked once I fast-traveled in a friend’s game)
- Bounty Hunter (20 side missions; unlocked at the same time as location achievements)
- Motörhead (all missions, Campaign of Carnage; unlocked after redoing level 3 of Pyro Pete’s bar fight)
The following do not want to unlock:
- Did It All (all side missions, main campaign)
- Gadabout (all locations, Pirate’s Booty)
- Completionist (all missions, Pirate’s Booty)
- Been There (all locations, Hammerlock’s Hunt)
- Done That (all missions, Hammerlock’s Hunt)
It seems that the achievements all need to increment some internal counter to re-check the unlock conditions. This is especially problematic for the locations, since everything is already discovered for my (main) character and stay discovered for additional playthroughs. I was able to unlock Completionist on my TVH playthrough since I had not yet done the mission for Master Gee, but I did not get Gadabout because his arena was already discovered (since I was there on Normal).
I’ll be redoing DLC areas with fresh characters, but it would be nice if the unlocks for location / side mission achievements were consistent.