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