Here is the full list of all 56 Mysterious Realms RPG achievements.
Slay the first enemy
Complete a mission when one Hero is dead
Unlock every feature in the Town
Reach the maximum of enemy's Health modif.
Solve a riddle
Slay the First Warden
Slay Elemental Lord
Slay Grim Reaper
Slay Goblin King
Slay a hidden enemy
Solve 3 riddles
Solve 8 riddles
Slay 10 enemies
Slay 25 enemies
Slay 100 enemies
Pick up 10 salvage
Pick up 40 salvage
Pick up 100 salvage
Complete a mission
Complete 10 missions
Complete 20 missions
Open 10 vases, barrels etc.
Open 50 vases, barrels etc.
Open 100 vases, barrels etc.
Teach Hero a skill
Teach every Hero 4 skills
Teach every Hero 6 skills
Slay a rare enemy
Slay 5 rare enemies
Slay 10 rare enemies
Light 5 torches
Light 50 torches
Light 100 torches
Drink 5 potions
Drink 15 potions
Drink 40 potions
Encounter a stranger
Encounter 3 strangers
Encounter 5 strangers
Pick up 30 gold
Pick up 100 gold
Pick up 200 gold
Eat 3 food
Eat 10 food
Eat 25 food
Examine 3 objects
Examine 8 objects
Examine 15 objects
Empower a Crystal up to 3 power
Empower every Crystal up to 3 power
Empower every Crystal up to 5 power
Encounter an Event
Encounter 10 Events
Encounter 25 Events
Complete the game without any Hero dying
Obtain every other achievement