Here is the full list of all 26 PictoQuest achievements. It takes around 8-10 hours to unlock all of the achievements on Windows.
Read the tutorial
Finish all quests
Beat Moonface
Beat the mountain boss
Beat the mangrove boss
Beat the seaside boss
Reach 0 gold
Buy all life extensions
Reach 5000 gold
Beat the desert boss
Beat the cave boss
Use the ice orb
Use the thunder orb
Beat the swamp boss
Use a potion
Loose 10 times
Make 20 mistakes
Beat the forest boss
Use the fire orb
Beat the plains boss
Have a full inventory
Beat the village boss
Finish a three-monster grid
Finish a two-monster grid
Finish a one-monster grid
Finish the first grid