There are a total of 17 shortcuts in the six main campaign levels. Once you've opened/unlocked them they'll remain unlocked for any future playthroughs.
The shortcuts are broken down as follows:
- Dubai - 4 shortcuts
- Dartmoor - 2 shortcuts
- Berlin - 3 shortcuts
- Chongqing - 3 shortcuts
- Mendoza - 3 shortcuts
- Carpathian mountains - 2 shortcuts (But if you get them in order you won't need these for the achievement.
Below I've linked youtuber MrFreeze2244
's video walkthroughs for unlocking all of the shortcuts (his walkthrough videos are, in my opinion, the best out there, I'd highly recommended checking out his videos if you're struggling with any challenges).
Update 30th March 2021:Dubai (4 shortcuts)Dartmoor (2 shortcuts)Berlin (3 shortcuts)Chongqing (3 shortcuts)Mendoza (3 shortcuts)Carpathian Mountains (2 shortcuts)
The March update includes a fix for those who haven't had this achievement unlock when it should have. See the patch notes here
, in particular: "Players that have been affected should unlock the relevant trophies/achievements when they launch the game after installing the 3.20 patch"
Note that this video actually covers all
the challenges for the Carpathian Mountains (except suit only / silent assassin). If you follow through from the start you'll unlock the first shortcut at 6:32, and the second at 9:24.