Here is the full list of all 20 Montague's Mount achievements.
You have walked 10 kilometres.
You have located the 22 crosses of St. Brigid of Kildare.
You have visited 4 of Montague's Mount's beaches.
You played the gramophone.
You have found the 5 MacLaughlin family graves.
You have been playing the games for 3 hours.
You have completed the candle puzzle in McKenna's dock.
You have found the 5 secret postcards that are hidden around the island.
You have opened the 4 puzzle gates.
You have been playing the game for 2 hours.
You have walked 1 kilometre.
Solved the Spinner Puzzle.
You have located the 4 coloured spinners for the bridge puzzle.
You have examined 100 objects.
You have lowered the bridge in Pitcairn Point.
You have been playing the game for 1 hour.
You have started the old generator.
You have located the Old Hermit's shack.
You have found the walking stick which makes your progress easier.
You have examined 25 objects.