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 5000 gold
Beat the cave boss
Use the thunder orb
Make 20 mistakes
Beat the swamp boss
Use the ice orb
Beat the forest boss
Beat the plains boss
Use the fire orb
Have a full inventory
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
Reach 0 gold
Beat Moonface
Beat the desert boss
Beat the seaside boss
Beat the mangrove boss
Beat the mountain boss
Buy all life extensions
Loose 10 times
Read the tutorial
Finish all quests