The negative not showing after beating satan 5 times?

[Acrylic]

So I beat Satan 4 times and somehow skipped the floor and beat the lamb before the 5th time. I've beaten him at least 5 times now but the negative never appears after I beat mom. My save file has "The end" with the lamb's skull so I don't know what I did.

[Nazemec]

According to your achievements, you haven't unlocked the Negative yet, so it's normal if it doesn't appear. Killing the Lamb earlier doesn't auto-unlock the Negative nor prevents you from unlocking it.

Reminder: Satan kills on seeded runs do not count, since seeds prevent progress.

[Acrylic]

Okay I was pretty sure I had unlocked it. Should have looked at my achievements haha. I don't do seeded runs so I guess I just have to keep beating him. I was afraid I had prevented myself from unlocking it

[The Renderer]

Just for future reference: It is impossible in this game to get locked out of anything. No matter the order in which you do things.

[Acrylic]

Rad. Thank you guys for the help!