烂 as 'terrible/awful' is very colloquial and common online. 烂片 (làn piàn) = bad movie, 烂人 (làn rén) = terrible person, 烂大街 = extremely common/everywhere.
usage
The cooking meaning is neutral/positive: 煮烂 (boil until soft). But in most other contexts, 烂 is strongly negative.
