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