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