THE LOST seeds and SOLUTION to unlock + STEAM Acheivement
You have to follow those four steps in The Binding of Isaac: Rebirth :
1. Playing as ISAAC die on 1st BASEMENT with MOOLIBOOM Seed: JTMDEZPF
2. Playing as MAGDALENE kill yourself with your own bomb at 1st CAVES Seed: 349WVRFT
3. Playing as JUDAS die with MOM's LEG hit.
4. Playing as AZAZEL die with 2nd stage of Devil (brimstone/tears shot attacks)
You have to do that in a ROW. If you die in another way/play another character you have to star all over again. Here you have 2nd stage od DEVIL