Here is the full list of all 14 Hidden Deep achievements.
Kill 1000 monsters
Ride a elevator from top to bottom non-stop. Yes, that's possible.
Complete a level with high enemy presence without dying (must be 50+ enemies)
Drill 100 meters of tunnel using the Tunnel Boring Machines
Fall from 50 meters or more
Let another team member use your rope to climb
Kill 3 enemies using one Scan-Ball
Find a hidden cave using the Terra-Scanner
Kill 20 enemies with your gun without dying
Use the grappling hook as a zip-line
Kill 100 monsters
Kill the ceiling tentacle before it kills you on your first encounter
Kill 5 enemies in a row while hanging on the grappling hook
Rappel down the full length of your grappling hook's line