There are 8 secret achievements. 3 require solving a specific nonogram and 5 is related to the guild.
- Play > Black-and-White Nonograms > 30 - 50 > Katana (40x30).
- Play > Black-and-White Nonograms > 30 - 50 > Kabuki (32x50).
- Play > Colored Nonograms > Colored Nonograms by belko61 Part 2 > Dream came true (75x75).
- Adventurers Guild > Airship > Complete 20 flights (to any destination).
- Adventurers Guild > Tailor > Craft Armor for a hero lvl. 4 (requires following Once Upon a Forest and researching various technologies).
- Adventurers Guild > Quests > Complete the quest: Once Upon a Forest.
- Adventurers Guild > Projects > Complete one project group (10 levels). Unlocking this achievement also requires investing in other project groups, because of project restrictions.
- Adventurers Guild > Train > Upgrade train to maximum level.
Solved nonogram: Katana (40x30).
Solved nonogram: Kabuki (32x50).
Solved nonogram: Dream came true (75x75).