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