Literally, 개 is dog, 꿀 is honey. 개 here functions as an adjective meaning "the utmost" or "greatly". English equiv would be RAD!!, or MAD!!.. Dog!!! 꿀honey is the sweetest and the sweetest part of something, as honey is the sweetest part harvested from a flower. it is my understanding that 개꿀 came from 개꿀잼, which is 개MAD+ 꿀SAAWEET+잼(재미, fun) While 개꿀잼 indicates the subject ur talking about is extremely fun and entertaining, 개꿀-although derived from 개꿀잼- often means that something is the core part of something, for example, I heard some infants saying 의대가 서울대의 개꿀이지 meaning the Medical school is the prime part of the Seoul National University. When you say this expression in spoken Korean you look extremely dumb and geeky and superficial- only use this anonymously on web forums.

Super easy to finish it. or something.