Sea Salt

Buggy! For some it doesnt count progress like it should. No known fix.

It doesnt matter what difficulty you play on!
(Im confused about the Hunter. I could have sworn i didnt get progress while playing on normal, but on my hard playthrough i got progress. So not sure about him. Needs further confirmation :/ Hard is confirmed by atleast two people.)

!!! As this seems buggy for a lot of people it might be viable to go directly for this achievement early on. Your first decision is directly after the first level/tutorial, takes ~5 minutes. If your counter shows progress just restart and repeat, takes about a hour in theory. Not confirmed if this works just a thought i had!

The only thing this achievement counts are the times when you have to make a decision between different routes you can take e.g. North or East.
From the percentages on the progress bar, i believe you have to make a decision 12 times to get the achievement. Thats why h3llzD0main got it after 4 playthroughs, there are 3 intersections in a playthrough.

In a perfect completion you'll have to play thrice on normal and once on hard leaving you with 12.
Theoretically if you are only going for this achievement you could play up to Karlshaven make the decision and start a new game, which takes around 5 minutes each time.

This achievement seems to have a misleading description and was likely not programmed properly.

On each run through the game, there are occasions where you choose a direction to continue. The counter would go up for me 8 or 9% each time I made one of these directional choices, meaning that the actual requirement for this achievement is to simply make any 12 directional choices over time.

I played through the game twice on normal to take all possible paths. Then I played through with the Hunter on hard and I was at 75% progress towards this achievement. So I simply played the first chapter (defeat Admiral Pierce), then chose a direction in the next area at which point I'd get progress towards the achievement, then repeated two more times.

Beat the game four times going through all routes. Two playthroughs on normal, taking the route not taken on the previous session and again on hard. That's how I did it, hope this helps.