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
Reach 0 gold
Reach 5000 gold
Beat the mountain boss
Use the thunder orb
Use the ice orb
Loose 10 times
Beat the mangrove boss
Beat the seaside boss
Read the tutorial
Beat the desert boss
Buy all life extensions
Beat the cave boss
Beat the swamp boss
Make 20 mistakes
Beat the forest boss
Beat the plains boss
Have a full inventory
Use a potion
Use the fire orb
Beat the village boss
Finish a three-monster grid
Finish a two-monster grid
Finish a one-monster grid
Finish the first grid