Here is the full list of all 21 Treasure of Nadia achievements. It takes around 40-50 hours to unlock all of the achievements on Windows.
Find everything in the game
Buy all the multivitamins
Find every Kamasutra page
Craft every item you can
Dig up a talisman of the gods
Dig up a royal talisman
Light all torches
Solve all ancient temple puzzles
Complete the main story
Dig up a grand talisman
Fully impress Jim
Buy everything from the bait shop
Catch a great white shark
Catch a hammerhead
Dig up a gold talisman
Dig up a silver talisman
Catch a tuna
Catch a seaperch
Catch a rockfish
Dig up a jade talisman
Dig up a stone talisman