Mysterious ingredient is a hidden achievement. Reveal the requirement and checklist below when you are ready for story spoilers.
Reveal hidden requirement and guidance
Unlock Mr. Thaddeus's secret room.
What to check
Community sources disagree about mansion lock labels. Match the actual device to its clue before treating a code entry as proof that the secret room was opened.
Record your progress
Use this local checklist for Mysterious ingredient. It does not connect to Steam or unlock anything in the game. Steam's own achievement state remains authoritative.
- Unlock Mr. Thaddeus's secret room.
- Confirm Mysterious ingredient is unlocked in Steam.
If the unlock does not appear
Keep the relevant objective or counter screenshot and your build information. A requirement description does not prove an unlock bug, and an older patch fix is not a guarantee for a new regression. Do not delete saves or use an achievement unlocker to troubleshoot.
Your checklist
0 / 2Saved on this browser only. No Steam connection.
Sources & build scope
Full release · official patch notes; not a local gameplay retest. Source review is separate from a gameplay test.
- Steam: global achievements ↗Tier A · Public names and visible conditions
- Steam: publicly unlocked achievement descriptions ↗Tier C · Player-visible hidden conditions; spoilers
- Impulzer: Safes & Secrets ↗Tier C · Community puzzle reports; conflicting labels retained
- GAMES.GG: puzzle clue cross-check ↗Tier C · August 17; mansion labels disagree with other sources