Andrew Plotkin uncovers a rare memory-corruption compiler bug in Infocom’s 1983 interactive fiction game Infidel

Andrew Plotkin says he found an unusually severe but hard-to-notice bug in Infidel while examining the game with a memory-level debugger. The issue appears to be a wild pointer caused by a compiler bug, affecting both the Macintosh update and the original release with different memory addresses.

The discovery shows how modern reverse-engineering and preservation tools can reveal defects that were nearly invisible to players for decades. It also highlights the technical fragility of early game runtimes, where small compiler or memory errors could persist unnoticed across releases.