A typo in an identifier inside a config script of one unreal-engine-based game worsened the game AI significantly. But it tooks five years to find the typo. (Lua was not the scripting language that the config was written in.)
The conclusions from this story: 1) Typos are hard-to-find bugs. 2) IMO, Lua have to somehow solve the problem of absence of warnings about misspelled identifiers.
