Here is the full list of all 25 Mount Wingsuit achievements.
Pull the parachute
Score a combo of at least 250K
Score a combo of at least 1 million
Complete all objectives, gaps and collectibles
Survive a box landing
Survive 50 box landings
Hit a tree
Die a 100 times
Fly through a mountain hole or tunnel
Visit old Rico
Collect all ninja whales
Collect all hidden orbs
Unlock all suits
Complete all gaps
Unlock all droppoints
Perform a rage quit
Perform a risky triple frontflip or backflip
Perform a risky quintuple frontflip or backflip
Perform a risky quadruple barrel roll
Perform a risky quintuple barrel roll
Complete all survival runs
Complete all record the pros
Fly for a total of one hour
Unlock droppoint 10
Hit a box landing bullseye