1. What does it mean?
밸붕 abbreviates 밸런스 붕괴, balance collapse. Gamers use it when one option, character, or team seems overwhelmingly favored. It also appears in everyday comparisons when the two choices are comically unequal.
Also written or said as 밸런스 붕괴, baelbung
2. The nuance
It is usually an opinion or exaggeration, not a measured verdict. Something being strong in one situation does not necessarily mean the entire game is broken.
3. Examples
“한 팀에 숙련자가 다 모여서 밸붕이네.”
All the experienced players ended up on one team, so this is wildly unbalanced.
“선택지 차이가 너무 커서 밸붕 질문이야.”
The options are so unequal that the question is barely a choice.
Sources
References support the meaning and usage. Example sentences are written for NoCapWiki.