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).
Dubai (4 shortcuts)Dartmoor (2 shortcuts)Berlin (3 shortcuts)Chongqing (3 shortcuts)Mendoza (3 shortcuts)Carpathian Mountains (2 shortcuts)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.