Here is the full list of all 77 Next Hero achievements.
Acquire all loot
Thank you for playing
Completed item collection
Establish a statue of all monsters in the museum
Completed monster collection
Kill the King Salamander
Kill the King Kobold
Kill the Chief Cannoneer
Drink more than 10 Potions
Marrying Diana
Acquire other items
Acquire all weapons
Kill the King Fire Slime
Acquire all armor
Killed the Elder.
Kill the King Skull
Achieve highest level of mercenaries
Achieve the monastery's highest level
Blacksmiths achieve highest level
Kill the King Bomb Slime
Have more than 30 Keys
Kill the Chief Ninja
Kill the King Lynx
Completed all the quests
Achieve the bar highest level
Achieve village level
Kill the King Toothtrap
Saw the credits.
Kill the King Zombie
Kill the King Yeti
Kill the Chief Mage
Marry Sofia
Kill the King Jellyfish
Left the Village
Kill the Dragon
First cleared Stage 5
Kill the Succubus
Kill the Knight Commander
Kill the Snow Worm
Building a museum in town
Death from purchasing items in a Dark shop
Kill the King Turtle
Kill the Chief Archer
Kill the King Bat
Kill the King Toad
Kill the King Goblin
Kill the King Cobra
Kill the Golem
Find a secret room more than 3 times in one game
Kill the King Ice Slime
Kill the King Octopus
Construction of a pub in a village
Monastery construction in the village
Construction of a blacksmith in a village
First cleared Stage 4
Kill the Horseman Commander
Collect 10 Hearts
First cleared Stage 3
Open more than 10 Boxes in a game
Kill the King Harpy
Have more than 30 Bombs
Kill the Siren
Kill the King Slime
Kill the King Mushroom
Construction of a mercenary small town
Enter the Colosseum 3 or more times in a game
First cleared Stage 2
Kill the King Shark
Kill more than 100 Monsters
Have more than 100 Golds
Have more than 10 Equipmets
First cleared Stage 1
Kill the King Rabbit Slime
First discovered a Secret room
Break more than 100 Objects