Check your email for keywords like "Butterfly Escape," "itch.io receipt," or "Game Jolt key." Step 2: If you bought via Steam/Epic, the key is already in your library. No re-entry needed. Step 3: If you bought a standalone key and lost it, email the developer directly at support@butterflyescapegame.com with your PayPal receipt or original purchase email address. Indie devs are notoriously helpful.
Cryptographers have been attempting to crack the code, and some claim to have made progress. One researcher, who wishes to remain anonymous, shared their findings: butterfly escape registration key