**REPORTED** Got "Slayer of Worlds" achievement without defeating all bosses

[Dropkickx86]

Steam or GOG

Steam

Single Player/Multiplayer

Single

Controls Used

Keyboard/Mouse

I recently defeated Duke Fishron after getting utterly defeated by Moon Lord (both for the first time). Whilst checking the wiki for random on my second monitor, I noticed a steam popup saying I got the "Slayer of Worlds" achievement. Remember how I said I got defeated by moon lord? That was the first time trying that boss. I have some others that are undefeated that I haven't even seen outside Youtube. Steam still show "Fish Out of Water" as my last achievement, even though I "got" "Slayer of Worlds" after that. Terrarias own achievement system claims I have defeated 14/15 of the bosses needed, so it doesn't count all bosses but definitely counts Moon Lord, as it should.

 

[Sigma90]

Welcome to the forums Dropkickx86!
The Slayer of Worlds achievement has always been a bit strange with Wall of Flesh and Duke Fishron. Sometimes it activates early for those bosses. But the next time you reload, the counter is back to what it should be. Fortunately this doesn't break progression; once you defeat all bosses required, the achievement unlocks permanently.
This is a known issue, but thank you for the report!