A strange little side quest
If Days 2 Die sends you down a curiosity rabbit hole, start here. Doom changed game design and distribution in 1993 by separating its engine from content and spreading widely through shareware. There is another connection worth keeping in the same mental pocket: The word 'checkmate' is linked to the Persian expression 'shah mat', used when the king was trapped. That is the kind of background detail that makes another attempt at Days 2 Die feel a bit more connected to the history of play.
