(SPOILERS!!! SKIP TO BOTTOM OF COMMENT!!!)
Odd question, but for those who have experienced the Haunted Kerfus and Killfus bossfight events, is there any way to refight Killfus? I killed it in the incinerator in the basement and it destroyed the yellow Kerfur color and didn't give me the achievement on that file.
(SPOILERS END HERE!!! SORRY ITCH HAS NO SPOILER TEXT OPTION THAT I CAN SEE!!!)